Treatment of cancer with anti-LAP monoclonal antibodies

ABSTRACT

Described herein are compositions and methods relating to LAP-binding agents, including, for example, anti-LAP antibodies, and to their use in methods of treatment of cancer. LAP-binding agents affected both systemic and intra-tumor immunity and were shown effective to treat a broad spectrum of cancer types.

RELATED APPLICATIONS

This application is a continuation of and claims priority under 35U.S.C. § 120 to U.S. patent application U.S. Ser. No. 15/649,373, filedJul. 13, 2017, which claims priority under 35 U.S.C. §§ 120 and 365(c)to and is a continuation of international PCT Application,PCT/US2016/013408, filed Jan. 14, 2016, which claims benefit under 35U.S.C. § 119(e) of U.S. Provisional Application No. 62/103,401, filedJan. 14, 2015, the contents of each of which is herein incorporated byreference in its entirety.

GOVERNMENT SUPPORT

This invention was made with government support under Grant NumberNS090163 awarded by the National Institutes of Health. The Governmenthas certain rights in the invention.

TECHNICAL FIELD

The technical field relates to anti-LAP antibodies and methods fortreating cancer.

BACKGROUND

According to the data from the World Health Organization, ten millionpeople around the world were diagnosed with cancer in 2000, and sixmillion died from it. Moreover, statistics indicate that the cancerincidence rate is on the rise around the globe. In the United States,for example, projections indicate that fifty percent of those alivetoday will be diagnosed with some form of cancer at some point in theirlives.

Cancer therapies include radiation, surgery, cytotoxic chemotherapeuticagents, treatments aimed at increasing cancer-specific immune responses,and combinations of such approaches. Recent approaches to cancer therapyhave focused on actively harnessing a patient's immune response totarget cancer cells using a variety of approaches, includingimmunization with tumor antigens, inhibition or removal ofsuppressive/regulatory immune cell populations, and activation ofexhausted immune cell populations.

SUMMARY

LAP or latency-associated peptide results from the separation of theN-terminal protein portion of TGF-β. LAP is secreted and can be found inthe extracellular matrix. In addition, LAP can also be expressed onplatelets. Importantly, as described herein, LAP is found on activatedregulatory T cells. The compositions and methods described herein arebased, in part, on the discoveries that tumor growth is lower and micesurvive longer when treated with anti-LAP antibodies, and that theanti-LAP antibodies described herein act, in part, by preventing orinhibiting TGF-β signaling (including by blocking the release of TGF-βfrom the LAP/TGF-b complex) and/or depleting both activated CD4+ andCD8+ regulatory T cell populations. More specifically, as shown herein,anti-LAP antibody treatment affected both systemic and intra-tumorimmunity as follows: (1) Tumors were infiltrated by increased numbers ofcytotoxic CD8+ T cells and intra-tumor Foxp3 Tregs were decreased. CD4+and CD8+ intra-tumor T cells had decreased expression of PD-1, LAG3 andCD103. (2) In the periphery, CD4+ and CD8+ T cells, expressing IFN-γ andgranzyme B, were increased, respectively whereas CD103+ T cells weredecreased. Finally, there were reduced numbers of tolerogenic dendriticcells expressing CD103 and PD-L1, whereas MHC II was elevated on splenicmyeloid cells. Anti-LAP antibodies showed efficacy in various cancermodels, including a GBM model, a melanoma model, and a colon carcinomamodel, and similar intra-tumor and peripheral immune effects wereobserved, indicating broad applicability of this approach for cancertherapy. Thus, as demonstrated herein, anti-LAP antibody stronglyinfluences systemic and intra-tumor immune responses by activating bothinnate and adaptive immunity and overcomes the mechanisms suppressingtumor-specific immunity. In conclusion, anti-LAP antibody as monotherapyor combined with conventional anti-tumor modalities represents a novelimmunotherapeutic approach for the treatment of cancer.

Accordingly, described herein is an isolated anti-LAP antibody orantigen-binding fragment thereof that specifically binds to LAPcomprising one or more heavy and light chain complimentarity determiningregions (CDRs) selected from the group consisting of: a) a heavy chainCDR1 having the amino acid sequence of SEQ ID NO: 9; b) a heavy chainCDR2 having the amino acid sequence of SEQ ID NO: 10; c) a heavy chainCDR3 having the amino acid sequence of SEQ ID NO: 11; d) a light chainCDR1 having the amino acid sequence of SEQ ID NO: 14; e) a light chainCDR2 having the amino acid sequence of SEQ ID NO: 15; and f) a lightchain CDR3 having the amino acid sequence of SEQ ID NO: 16.

In one embodiment, the isolated anti-LAP antibody or antigen-bindingfragment thereof comprises the heavy chain complimentarity determiningregions (CDRs): a) a heavy chain CDR1 having the amino acid sequence ofSEQ ID NO: 9; b) a heavy chain CDR2 having the amino acid sequence ofSEQ ID NO: 10; and c) a heavy chain CDR3 having the amino acid sequenceof SEQ ID NO: 11.

In another embodiment, the isolated anti-LAP antibody or antigen-bindingfragment thereof comprises the light chain complimentarity determiningregions (CDRs): a) a light chain CDR1 having the amino acid sequence ofSEQ ID NO: 14; b) a light chain CDR2 having the amino acid sequence ofSEQ ID NO: 15; and c) a light chain CDR3 having the amino acid sequenceof SEQ ID NO: 16.

In another embodiment, the isolated anti-LAP antibody or antigen-bindingfragment thereof comprises the complimentarity determining regions(CDRs): a) a heavy chain CDR1 having the amino acid sequence of SEQ IDNO: 9; b) a heavy chain CDR2 having the amino acid sequence of SEQ IDNO: 10; c) a heavy chain CDR3 having the amino acid sequence of SEQ IDNO: 11; c) a light chain CDR1 having the amino acid sequence of SEQ IDNO: 14; e) a light chain CDR2 having the amino acid sequence of SEQ IDNO: 15; and f) a light chain CDR3 having the amino acid sequence of SEQID NO: 16.

In another embodiment, the isolated anti-LAP antibody or antigen-bindingfragment thereof comprises a heavy chain having the amino acid sequenceof SEQ ID NO: 8.

In another embodiment, the isolated anti-LAP antibody or antigen-bindingfragment thereof comprises a light chain having the sequence of SEQ IDNO: 13.

In another embodiment, the isolated anti-LAP antibody or antigen-bindingfragment thereof comprises a) a heavy chain CDR1 having the amino acidsequence of SEQ ID NO: 9; b) a heavy chain CDR2 having the amino acidsequence of SEQ ID NO: 10; c) a heavy chain CDR3 having the amino acidsequence of SEQ ID NO: 11; d) a light chain CDR1 having the amino acidsequence of SEQ ID NO: 14; e) a light chain CDR2 having the amino acidsequence of SEQ ID NO: 15; and f) a light chain CDR3 having the aminoacid sequence of SEQ ID NO: 16.

In another embodiment, the isolated anti-LAP antibody or antigen-bindingfragment comprises one or more heavy chain complimentarity determiningregions (CDRs) selected from the group consisting of: a) a heavy chainCDR1 having the amino acid sequence of SEQ ID NO: 9; b) a heavy chainCDR2 having the amino acid sequence of SEQ ID NO: 10; and c) a heavychain CDR3 having the amino acid sequence of SEQ ID NO: 11.

In another embodiment, the isolated anti-LAP antibody or antigen-bindingfragment comprises one or more light chain complimentarity determiningregions (CDRs) selected from the group consisting of: a) a light chainCDR1 having the amino acid sequence of SEQ ID NO: 14; b) a light chainCDR2 having the amino acid sequence of SEQ ID NO: 15; and c) a lightchain CDR3 having the amino acid sequence of SEQ ID NO: 16.

The antibody for any aspect described herein can be a monoclonalantibody. In certain embodiments, the antibody of any aspect describedherein is a chimeric, CDR-grafted, humanized, composite human or fullyhuman antibody or dual antibody or antigen-binding fragment thereof. Inother embodiments of any aspect described herein, the antibody fragmentis a Fab fragment, a Fab′ fragment, a Fd fragment, a Fd′ fragment, a Fvfragment, a dAb fragment, a F(ab′)₂ fragment, a single chain fragment, adiabody, or a linear antibody. In another embodiment of any aspectdescribed herein, the antibody or antigen-binding fragment thereofcomprises a human acceptor framework. The monoclonal antibody upon whichany of these embodiments is based can include, for example, themonoclonal antibody produced by a hybridoma clone selected from thegroup designated TW4-9E7, TW4-5A8, TW4-4E5, TW4-12B12, TW4-1G12,TW4-3G5, TW4-2F8, TW4-6H10, TW4-1G2, TW4-1E1, TW4-16F4, TW4-8F10,TW4-3H6, TW4-2C9, TW7-16B4, TW7-28G11, TW7-7H4, and TW7-20B9.

Also described is a composition comprising a LAP-binding agent and aninhibitor of TGF-β signaling.

In one embodiment, the LAP-binding agent comprises an anti-LAP antibodyor antigen-binding fragment thereof. In another embodiment, the antibodyis a monoclonal antibody. In another embodiment, the antibody ischimeric, CDR-grafted, humanized or fully human. In another embodiment,the antibody comprising one or more, two or more, three or more, four ormore, five or more, or all six of the heavy and light chaincomplimentarity determining regions (CDRs) including a) a heavy chainCDR1 having the amino acid sequence of SEQ ID NO: 9; b) a heavy chainCDR2 having the amino acid sequence of SEQ ID NO: 10; c) a heavy chainCDR3 having the amino acid sequence of SEQ ID NO: 11; d) a light chainCDR1 having the amino acid sequence of SEQ ID NO: 14; e) a light chainCDR2 having the amino acid sequence of SEQ ID NO: 15; and f) a lightchain CDR3 having the amino acid sequence of SEQ ID NO: 16.

In another embodiment, the inhibitor of TGF-β signaling is selected fromthe group consisting of an antibody or antigen-binding fragment thereofthat binds TGF-β or a receptor therefor, a double-stranded RNA ornucleic acid encoding a double-stranded RNA, an aptamer, and a smallmolecule. Antibodies that specifically bind and inhibit signaling byTGF-β and TGF-β receptors are known in the art and include commerciallyavailable antibodies. Double stranded RNAs that specifically targetTGF-β and/or TGF-β receptors via RNA interference are also known in theart and commercially available. Small molecule inhibitors of TGF-bsignaling are known in the art and include, for example,4-[4-(1,3-benzodioxol-5-yl)-5-pyridin-2-yl-1H-imidazol-2-yl]benzamide(SB431542),N-(oxan-4-yl)-4-[4-(5-pyridin-2-yl-1H-pyrazol-4-yl)pyridin-2-yl]benzamide(GW788388), 4-[3-(2-Pyridinyl)-1H-pyrazol-4-yl]-quinoline (LY364947),and 2-(3-(6-methylpyridin-2-yl)-1H-pyrazol-4-yl)-1,5-naphthyridine(“ALK5 Inhibitor II”).

Also described is a composition comprising a LAP-binding agent and animmunomodulatory or chemotherapeutic agent.

In one embodiment, the LAP-binding agent comprises an antibody orantigen-binding fragment thereof. In another embodiment, the antibody orantigen-binding fragment thereof is a monoclonal antibody orantigen-binding fragment thereof. In certain embodiments, the antibodyor antigen-binding fragment thereof is chimeric, CDR-grafted, humanizedor fully human. In another embodiment, the antibody comprises one ormore, two or more, three or more, four or more, five or more, or all sixof the heavy and light chain complimentarity determining regions (CDRs)including a) a heavy chain CDR1 having the amino acid sequence of SEQ IDNO: 9; b) a heavy chain CDR2 having the amino acid sequence of SEQ IDNO: 10; c) a heavy chain CDR3 having the amino acid sequence of SEQ IDNO: 11; d) a light chain CDR1 having the amino acid sequence of SEQ IDNO: 14; e) a light chain CDR2 having the amino acid sequence of SEQ IDNO: 15; and f) a light chain CDR3 having the amino acid sequence of SEQID NO: 16.

In another embodiment, the immunomodulatory agent comprises an immunecheckpoint modulator Immune checkpoint protein receptors and theirligands (referred to herein collectively as checkpoint proteins) mediatesuppression of T cell mediated cytotoxicity and are often expressed bytumors or on anergic T cells in the tumor microenvironment and permitthe tumor to evade immune attack. Inhibitors of the activity ofimmunosuppressive checkpoint protein receptors and their ligands canovercome the immunosuppressive tumor environment to permit cytotoxic Tcell attack of the tumor. Examples of immune checkpoint proteinsinclude, but are not limited to PD-1, PD-L1, PDL2, CTLA4, LAG3, TIM3,TIGIT, and CD103. Modulation, including inhibition, of the activity ofsuch proteins can be accomplished by an immune checkpoint modulator,which can include, for example, antibodies, aptamers, small moleculesand soluble versions of checkpoint receptor proteins, among others, thattarget the checkpoint proteins. PD-1-targeting inhibitors include theapproved drug agents pembrolizumab and nivolumab, and ipilimumab is anapproved CTLA-4 inhibitor. Antibodies specific for PD-L1, PD-L2, LAG3,TIM3, TIGIT and CD103 are known and/or commercially available and canalso be produced by those of skill in the art.

Immunomodulatory agents include, in addition to immune checkpointmodulators, agents that facilitate or mediate antigen presentation thatpromotes a cell-mediated immune response. Such immunomodulators caninclude, for example, a tumor antigen vaccine. A tumor antigen vaccinecan include a preparation comprising a particular tumor antigen or setof known tumor antigens, with or without a subject's own dendritic cellsor an adjuvant. Alternatively, a tumor antigen vaccine can comprise arelatively crude preparation of tumor cell antigens from a patient'stumor, which, when exposed ex vivo to dendritic cells generated in vitrofrom a patient's cells can permit T cell-mediated attack of the tumorwhen the dendritic cell vaccine is introduced to the patient. In oneembodiment, then, an immunomodulatory agent comprises a tumor antigenvaccine. In another embodiment, the tumor antigen vaccine comprises adendritic cell tumor antigen vaccine.

Also described herein is an antibody or antigen-binding fragment thereofthat binds to LAP when complexed with TGF-β and inhibits release ofTGF-β from the LAP/TGF-β complex. In one embodiment, the antibody orantigen-binding fragment binds an epitope formed by the binding of LAPto TGF-β. In another embodiment, the antibody or antigen-bindingfragment is a monoclonal antibody or antigen-binding fragment thereof,and can include, for example, a chimeric, CDR-grafted, humanized orfully human antibody or antigen-binding fragment thereof. In anotherembodiment, the antibody or antigen-binding fragment thereof comprisesone or more, two or more, three or more, four or more, five or more, orall six of the heavy and light chain complimentarity determining regions(CDRs) including a) a heavy chain CDR1 having the amino acid sequence ofSEQ ID NO: 9; b) a heavy chain CDR2 having the amino acid sequence ofSEQ ID NO: 10; c) a heavy chain CDR3 having the amino acid sequence ofSEQ ID NO: 11; d) a light chain CDR1 having the amino acid sequence ofSEQ ID NO: 14; e) a light chain CDR2 having the amino acid sequence ofSEQ ID NO: 15; and f) a light chain CDR3 having the amino acid sequenceof SEQ ID NO: 16. The antibody or antigen-binding fragment thereofencompasses the antibody produced, for example, by the hybridoma cloneTW7-28G11. The antibody or antigen-binding fragment thereof can alsoencompass the antibody produced, for example, by any of the otheranti-LAP hybridoma clones described herein.

Also described herein are pharmaceutical compositions comprising aLAP-binding agent or an antibody that specifically binds LAP, including,for example, human LAP, as described herein, and a pharmaceuticallyacceptable carrier. For any composition administered to an individual inneed thereof in a method as described herein, the amount of thecomposition will be a “therapeutically effective amount” as that term isdefined herein.

Also described herein is method of decreasing the number or activity ofa population of LAP+ T Regulatory cells in a subject, the methodcomprising administering a LAP-binding agent to the subject, whereby thenumber or activity of the LAP+ T regulatory cell population isdecreased.

As used herein, the terms “regulatory T cells” or “T regulatory cells”or “Tregs” refer to any population of CD4+ or CD8+ T cells that inhibitsor suppresses the activation, proliferation and/or effector functions ofother immune cells, including other CD4+ and CD8+ T cells, and helps tomaintain self-tolerance. Tregs are also sometimes referred to in olderliterature as suppressor T cells. CD4+CD25+FoxP3+ Tregs are a populationof regulatory T cells derived from the thymus and are a relativelyhomogeneous population until they migrate to the periphery, where asubpopulation can develop phenotypic characteristics similar toconventional memory and effector T cells. Cells of this subpopulationcan migrate to lymphoid and non-lymphoid tissues to maintain properimmune homeostasis. Peripherally-derived or so-called induced Tregs area population of regulatory T cells that can develop from conventionalCD4+CD25-FoxP3− T cells in the periphery. CD4+ Tregs are generally CD4+and FoxP3+, although the marker profiles can vary depending uponsource—for example, thymically-derived Tregs express high levels of themarker Helios, while induced Tregs do not. Not all induced Tregs expressCD25 or FoxP3. Unlike conventional T cells, some Treg cells express bothGARP and LAP/TGFβ transiently on their cell surface upon T cell receptoractivation. CD103+CD8+ Tregs are a population of regulatory T cells thatmediate antigen-specific suppression by production of the cytokinesIL-10 and/or TGF-β and/or by a direct inhibitory action on dendriticcells. Exemplary assays for identifying and/or characterizing thefunction of regulatory T cell populations are known in the art and aredescribed, for example, in Collison and Vignali, In Vitro TregSuppression Assays, METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) ⋅JANUARY 2011, the contents of which are herein incorporated by referencein their entireties. Typically, regulatory T cell function is identifiedby measuring suppression of proliferation in vitro, ex vivo, or in vivo.For example, an exemplary basic type of in vitro Treg suppression assayis one where Treg function is measured in the absence ofantigen-presenting cells (APCs). This assay includes only two celltypes, the target Tconv and Tregs, which are mixed together at variousratios, typically starting at a 2:1 ratio and stimulated using anti-CD3and anti-CD28, for example, using beads. Suppressive function of theTreg population is determined by measuring cellular proliferation,using, for example, a thymidine incorporation assay or using afluorescent dye-based assay, such as a carboxyfluorescein succinimidylester (CFSE) dilution assay.

As reported herein, a population of Tregs of particular interest is LAP+Tregs, which can accumulate in tumor tissues, among other sites. Asreported herein, a LAP-binding agent can decrease the number or activityof LAP+ Tregs, including the number or activity of tumor-infiltrated ortumor-associated Tregs. Reduction of the immunosuppression mediated byLAP+ Tregs can permit effective immune attack of the tumor. In oneembodiment, the LAP-binding agent can be an antibody or antigen-bindingfragment thereof. In one embodiment, the antibody can be a monoclonalantibody or antigen-binding fragment thereof. In another embodiment, theantibody or antigen-binding fragment thereof can be chimeric,CDR-grafted, humanized or fully human. In another embodiment, theantibody or antigen-binding fragment thereof comprises one or more, twoor more, three or more, four or more, five or more, or all six of theheavy and light chain complimentarity determining regions (CDRs)including a) a heavy chain CDR1 having the amino acid sequence of SEQ IDNO: 9; b) a heavy chain CDR2 having the amino acid sequence of SEQ IDNO: 10; c) a heavy chain CDR3 having the amino acid sequence of SEQ IDNO: 11; d) a light chain CDR1 having the amino acid sequence of SEQ IDNO: 14; e) a light chain CDR2 having the amino acid sequence of SEQ IDNO: 15; and f) a light chain CDR3 having the amino acid sequence of SEQID NO: 16. The antibody or antigen-binding fragment thereof encompassesthe antibody produced, for example, by the hybridoma clone TW7-28G11.The antibody or antigen-binding fragment thereof can also encompass theantibody produced, for example, by any of the other anti-LAP hybridomaclones described herein. While unconjugated antibody can be effective,in one embodiment, the LAP-binding agent can be conjugated to acytotoxic or chemotherapeutic agent or drug.

Not only are LAP+ Tregs reduced by administering a LAP-binding agent,but FoxP3+ Tregs are also reduced. Thus, also described herein is amethod of decreasing the number of FoxP3+ regulatory T cells in a tumor,the method comprising administering a LAP-binding agent to the subject.As with other aspects described herein, in one embodiment, theLAP-binding agent can be an antibody or antigen-binding fragmentthereof. In one embodiment, the antibody can be a monoclonal antibody orantigen-binding fragment thereof. In another embodiment, the antibody orantigen-binding fragment thereof can be chimeric, CDR-grafted, humanizedor fully human. In another embodiment, the antibody or antigen-bindingfragment thereof comprises one or more, two or more, three or more, fouror more, five or more, or all six of the heavy and light chaincomplimentarity determining regions (CDRs) including a) a heavy chainCDR1 having the amino acid sequence of SEQ ID NO: 9; b) a heavy chainCDR2 having the amino acid sequence of SEQ ID NO: 10; c) a heavy chainCDR3 having the amino acid sequence of SEQ ID NO: 11; d) a light chainCDR1 having the amino acid sequence of SEQ ID NO: 14; e) a light chainCDR2 having the amino acid sequence of SEQ ID NO: 15; and f) a lightchain CDR3 having the amino acid sequence of SEQ ID NO: 16. The antibodyor antigen-binding fragment thereof encompasses the antibody produced,for example, by the hybridoma clone TW7-28G11. The antibody orantigen-binding fragment thereof can also encompass the antibodyproduced, for example, by any of the other anti-LAP hybridoma clonesdescribed herein. While unconjugated antibody can be effective, in oneembodiment, the LAP-binding agent can be conjugated to a cytotoxic orchemotherapeutic agent or drug.

Also described herein is a method of decreasing the number or activityof tumor-infiltrated immunosuppressive T cells in a tumor, the methodcomprising administering a LAP-binding agent to a subject with a tumorcomprising tumor-infiltrated immunosuppressive T cells, whereby thenumber or activity of such cells is decreased. In one embodiment, theLAP-binding agent can be an antibody or antigen-binding fragmentthereof. In one embodiment, the antibody can be a monoclonal antibody orantigen-binding fragment thereof. In another embodiment, the antibody orantigen-binding fragment thereof can be chimeric, CDR-grafted, humanizedor fully human. In another embodiment, the antibody or antigen-bindingfragment thereof comprises one or more, two or more, three or more, fouror more, five or more, or all six of the heavy and light chaincomplimentarity determining regions (CDRs) including a) a heavy chainCDR1 having the amino acid sequence of SEQ ID NO: 9; b) a heavy chainCDR2 having the amino acid sequence of SEQ ID NO: 10; c) a heavy chainCDR3 having the amino acid sequence of SEQ ID NO: 11; d) a light chainCDR1 having the amino acid sequence of SEQ ID NO: 14; e) a light chainCDR2 having the amino acid sequence of SEQ ID NO: 15; and f) a lightchain CDR3 having the amino acid sequence of SEQ ID NO: 16. The antibodyor antigen-binding fragment thereof encompasses the antibody produced,for example, by the hybridoma clone TW7-28G11. The antibody orantigen-binding fragment thereof can also encompass the antibodyproduced, for example, by any of the other anti-LAP hybridoma clonesdescribed herein. While unconjugated antibody can be effective, in oneembodiment, the LAP-binding agent can be conjugated to a cytotoxic orchemotherapeutic agent or drug.

Where LAP-binding agents are demonstrated herein to reduceimmunosuppressive T cell populations, including immunosuppressive Tcells associated with or infiltrated within tumor tissue, it followsthat tumor specific immunity can be increased using a LAP-binding agentas described herein. Thus, this provides a method of increasingtumor-specific immunity comprising administering a therapeuticallyeffective amount of a LAP-binding agent to a subject in need thereof.This also provides a method of treating a cancer or tumor where LAPexpression and/or activity is associated with suppression of cancer- ortumor-specific immunity, the method comprising administering atherapeutically effective amount of a LAP-binding agent to a subject inneed thereof. In these aspects, as in others described herein, theLAP-binding agent administered can include, for example, an antibody orantigen-binding fragment thereof. In one embodiment, the antibody can bea monoclonal antibody or antigen-binding fragment thereof. In anotherembodiment, the antibody or antigen-binding fragment thereof can bechimeric, CDR-grafted, humanized or fully human. In another embodiment,the antibody or antigen-binding fragment thereof comprises one or more,two or more, three or more, four or more, five or more, or all six ofthe heavy and light chain complimentarity determining regions (CDRs)including a) a heavy chain CDR1 having the amino acid sequence of SEQ IDNO: 9; b) a heavy chain CDR2 having the amino acid sequence of SEQ IDNO: 10; c) a heavy chain CDR3 having the amino acid sequence of SEQ IDNO: 11; d) a light chain CDR1 having the amino acid sequence of SEQ IDNO: 14; e) a light chain CDR2 having the amino acid sequence of SEQ IDNO: 15; and f) a light chain CDR3 having the amino acid sequence of SEQID NO: 16. The antibody or antigen-binding fragment thereof encompassesthe antibody produced, for example, by the hybridoma clone TW7-28G11.The antibody or antigen-binding fragment thereof can also encompass theantibody produced, for example, by any of the other anti-LAP hybridomaclones described herein. While unconjugated antibody can be effective,in one embodiment, the LAP-binding agent can be conjugated to acytotoxic or chemotherapeutic agent or drug.

As described herein, it was discovered that treatment with a LAP-bindingagent not only reduces the number of LAP+ and FoxP3+ Tregs in a tumor,it also increases the number of CD8+ cytotoxic T cells in a tumor. Thus,also described herein is a method of increasing the number of CD8+cytotoxic T cells in a tumor, the method comprising administering, to asubject with a tumor, a LAP-binding agent. In this aspect, as in othersdescribed herein, the LAP-binding agent administered can include, forexample, an antibody or antigen-binding fragment thereof. In oneembodiment, the antibody can be a monoclonal antibody or antigen-bindingfragment thereof. In another embodiment, the antibody or antigen-bindingfragment thereof can be chimeric, CDR-grafted, humanized or fully human.In another embodiment, the antibody or antigen-binding fragment thereofcomprises one or more, two or more, three or more, four or more, five ormore, or all six of the heavy and light chain complimentaritydetermining regions (CDRs) including a) a heavy chain CDR1 having theamino acid sequence of SEQ ID NO: 9; b) a heavy chain CDR2 having theamino acid sequence of SEQ ID NO: 10; c) a heavy chain CDR3 having theamino acid sequence of SEQ ID NO: 11; d) a light chain CDR1 having theamino acid sequence of SEQ ID NO: 14; e) a light chain CDR2 having theamino acid sequence of SEQ ID NO: 15; and f) a light chain CDR3 havingthe amino acid sequence of SEQ ID NO: 16. The antibody orantigen-binding fragment thereof encompasses the antibody produced, forexample, by the hybridoma clone TW7-28G11. The antibody orantigen-binding fragment thereof can also encompass the antibodyproduced, for example, by any of the other anti-LAP hybridoma clonesdescribed herein. While unconjugated antibody can be effective, in oneembodiment, the LAP-binding agent can be conjugated to a cytotoxic orchemotherapeutic agent or drug.

In addition to effects on the number and/or activity of CD8+ cytotoxic Tcells, it was also discovered that treatment with a LAP-binding agentcan increase the population of peripheral CD4+ T cells expressing IFNγ.Thus, also described herein is a method of increasing peripheral CD4+ Tcells expressing IFNγ in a subject in need thereof, the methodcomprising administering a LAP-binding agent to the subject. Measurementof IFNγ production or secretion by CD4+ T cells is known to those ofskill in the art and/or described elsewhere herein. In this aspect, asin others described herein, the LAP-binding agent administered caninclude, for example, an antibody or antigen-binding fragment thereof.In one embodiment, the antibody can be a monoclonal antibody orantigen-binding fragment thereof. In another embodiment, the antibody orantigen-binding fragment thereof can be chimeric, CDR-grafted, humanizedor fully human. In another embodiment, the antibody or antigen-bindingfragment thereof comprises one or more, two or more, three or more, fouror more, five or more, or all six of the heavy and light chaincomplimentarity determining regions (CDRs) including a) a heavy chainCDR1 having the amino acid sequence of SEQ ID NO: 9; b) a heavy chainCDR2 having the amino acid sequence of SEQ ID NO: 10; c) a heavy chainCDR3 having the amino acid sequence of SEQ ID NO: 11; d) a light chainCDR1 having the amino acid sequence of SEQ ID NO: 14; e) a light chainCDR2 having the amino acid sequence of SEQ ID NO: 15; and f) a lightchain CDR3 having the amino acid sequence of SEQ ID NO: 16. The antibodyor antigen-binding fragment thereof encompasses the antibody produced,for example, by the hybridoma clone TW7-28G11. The antibody orantigen-binding fragment thereof can also encompass the antibodyproduced, for example, by any of the other anti-LAP hybridoma clonesdescribed herein. While unconjugated antibody can be effective, in oneembodiment, the LAP-binding agent can be conjugated to a cytotoxic orchemotherapeutic agent or drug.

Also described herein is a method of inhibiting expression of animmunosuppressive factor or marker by CD8+ and/or CD4+ T cells in atumor, the method comprising administering a LAP-binding agent to asubject with a tumor Immunosuppressive factors or markers produced byCD8+ and CD4+ T cells in a tumor include, for example, PD-1, LAG3 andCD103, among others, and inhibit T cell proliferation or responsivenessto stimulation, including, for example, T cell receptor stimulation orantigen stimulation. In this aspect, as in others described herein, theLAP-binding agent administered can include, for example, an antibody orantigen-binding fragment thereof. In one embodiment, the antibody can bea monoclonal antibody or antigen-binding fragment thereof. In anotherembodiment, the antibody or antigen-binding fragment thereof can bechimeric, CDR-grafted, humanized or fully human. In another embodiment,the antibody or antigen-binding fragment thereof comprises one or more,two or more, three or more, four or more, five or more, or all six ofthe heavy and light chain complimentarity determining regions (CDRs)including a) a heavy chain CDR1 having the amino acid sequence of SEQ IDNO: 9; b) a heavy chain CDR2 having the amino acid sequence of SEQ IDNO: 10; c) a heavy chain CDR3 having the amino acid sequence of SEQ IDNO: 11; d) a light chain CDR1 having the amino acid sequence of SEQ IDNO: 14; e) a light chain CDR2 having the amino acid sequence of SEQ IDNO: 15; and f) a light chain CDR3 having the amino acid sequence of SEQID NO: 16. The antibody or antigen-binding fragment thereof encompassesthe antibody produced, for example, by the hybridoma clone TW7-28G11.The antibody or antigen-binding fragment thereof can also encompass theantibody produced, for example, by any of the other anti-LAP hybridomaclones described herein. While unconjugated antibody can be effective,in one embodiment, the LAP-binding agent can be conjugated to acytotoxic or chemotherapeutic agent or drug.

It was also found that administering a tumor antigen or tumor antigenvaccine in conjunction with a LAP-binding agent promoted an anti-tumorimmune response. This approach can supplement, for example, tumorantigen vaccine therapeutic approaches. Thus, also described herein is amethod of promoting an anti-tumor immune response, the method comprisingvaccinating a subject in need of treatment for a tumor with a tumorantigen and administering a LAP-binding agent to the subject. Tumorantigens, and tumor antigen vaccines are known in the art and describedelsewhere herein. In this aspect, as in others described herein, theLAP-binding agent administered can include, for example, an antibody orantigen-binding fragment thereof. In one embodiment, the antibody can bea monoclonal antibody or antigen-binding fragment thereof. In anotherembodiment, the antibody or antigen-binding fragment thereof can bechimeric, CDR-grafted, humanized or fully human. In another embodiment,the antibody or antigen-binding fragment thereof comprises one or more,two or more, three or more, four or more, five or more, or all six ofthe heavy and light chain complimentarity determining regions (CDRs)including a) a heavy chain CDR1 having the amino acid sequence of SEQ IDNO: 9; b) a heavy chain CDR2 having the amino acid sequence of SEQ IDNO: 10; c) a heavy chain CDR3 having the amino acid sequence of SEQ IDNO: 11; d) a light chain CDR1 having the amino acid sequence of SEQ IDNO: 14; e) a light chain CDR2 having the amino acid sequence of SEQ IDNO: 15; and f) a light chain CDR3 having the amino acid sequence of SEQID NO: 16. The antibody or antigen-binding fragment thereof encompassesthe antibody produced, for example, by the hybridoma clone TW7-28G11.The antibody or antigen-binding fragment thereof can also encompass theantibody produced, for example, by any of the other anti-LAP hybridomaclones described herein. While unconjugated antibody can be effective,in one embodiment, the LAP-binding agent can be conjugated to acytotoxic or chemotherapeutic agent or drug.

While cancer treatment with immune checkpoint inhibitors can beeffective in overcoming the immunosuppression exploited by tumors toavoid immune attack, some types of cancer are, or can become, refractoryto treatment with checkpoint inhibitors. For example, certain cancers,including certain glioblastomas, melanomas and colorectal carcinomas,among others, tend to be refractory to treatment with inhibitors of PD-1and its receptors. Treatment with a LAP-binding agent can be effectiveto promote an anti-tumor immune response in these cancers, and it iscontemplated that such treatment can also restore or establishsensitivity of such cancers to the checkpoint inhibitor(s). Thus,described herein is a method of treating cancer that is refractory totreatment with an immune checkpoint inhibitor, the method comprisingadministering to a subject having such cancer a LAP-binding agent. Inthis aspect, as in others described herein, the LAP-binding agentadministered can include, for example, an antibody or antigen-bindingfragment thereof. In one embodiment, the antibody can be a monoclonalantibody or antigen-binding fragment thereof. In another embodiment, theantibody or antigen-binding fragment thereof can be chimeric,CDR-grafted, humanized or fully human. In another embodiment, theantibody or antigen-binding fragment thereof comprises one or more, twoor more, three or more, four or more, five or more, or all six of theheavy and light chain complimentarity determining regions (CDRs)including a) a heavy chain CDR1 having the amino acid sequence of SEQ IDNO: 9; b) a heavy chain CDR2 having the amino acid sequence of SEQ IDNO: 10; c) a heavy chain CDR3 having the amino acid sequence of SEQ IDNO: 11; d) a light chain CDR1 having the amino acid sequence of SEQ IDNO: 14; e) a light chain CDR2 having the amino acid sequence of SEQ IDNO: 15; and f) a light chain CDR3 having the amino acid sequence of SEQID NO: 16. The antibody or antigen-binding fragment thereof encompassesthe antibody produced, for example, by the hybridoma clone TW7-28G11.The antibody or antigen-binding fragment thereof can also encompass theantibody produced, for example, by any of the other anti-LAP hybridomaclones described herein. While unconjugated antibody can be effective,in one embodiment, the LAP-binding agent can be conjugated to acytotoxic or chemotherapeutic agent or drug. In one embodiment, themethod further comprises administering an immune checkpoint inhibitor,which can include, but is not limited to a checkpoint inhibitor to whichthe cancer was refractory. In one embodiment, the cancer is aglioblastoma, colorectal carcinoma or a melanoma. In one embodiment, thecancer is refractory to a PD-1 or PD-L1 inhibitor before treatment withthe LAP-binding agent.

Where it is demonstrated herein that treatment with a LAP-binding agentcan be effective for overcoming tumor immunosuppression, also describedherein are methods in which patients are selected for treatment and/orfor expected or predicted treatment efficacy on the basis of thepresence (detection) and/or amount (quantitative detection) of LAP+Tregs present in a patient's tumor. It follows that if LAP+ Tregs arepresent and/or present in significant number relative to a reference,the patient will be more likely to respond to treatment with aLAP-binding agent as described herein. Thus, also described herein is amethod for identifying or selecting a patient with a tumor that islikely to respond to therapy with a LAP-binding agent, the methodcomprising analyzing a tumor sample from a subject to determine thepresence of LAP+ T regulatory cells, and, if LAP+ T regulatory cells arepresent or are present in significant number relative to a reference. Ifthe patient's tumor has LAP+ Tregs or has, for example, a significantnumber relative to a reference, the patient is identified a having atumor likely to respond to treatment with a LAP-binding agent. For suchpatients, the method can further comprise treatment, comprisingadministering to the subject a LAP-binding agent, thereby promoting ananti-tumor immune response. As one example, the reference can be thenumber of LAP+ Treg cells present in a tumor known to have beeneffectively treated with a LAP-binding agent. In this embodiment, if thenumber of LAP+ Treg cells in a patient's tumor is, for example, at least20% or more of such a reference (i.e., in a significant number relativeto the reference, as that term is used herein), the patient would bemore likely to respond to treatment with a LAP-binding agent than if thenumber in the patient's tumor were below that level. If the patient'stumor is found not to have LAP+ Tregs or is found to have a considerablylower level of LAP+ Tregs relative to a reference, treatment with aLAP-binding agent, it may still be possible that treatment with aLAP-binding agent will facilitate treatment, but it is less likely thanwhere the level is higher. In such instances, the patient is identifiedas less likely to respond to a LAP-binding agent, and other therapeuticapproaches such as administering an immunomodulatory or anti-tumor agentother than a LAP-binding agent to the patient can be considered orcarried out. Non-limiting examples of such therapeutic approaches caninclude, for example, administering an immune checkpoint inhibitor, achemotherapeutic agent and/or gamma radiation.

In this aspect, as in others described herein, the LAP-binding agentadministered can include, for example, an antibody or antigen-bindingfragment thereof. In one embodiment, the antibody can be a monoclonalantibody or antigen-binding fragment thereof. In another embodiment, theantibody or antigen-binding fragment thereof can be chimeric,CDR-grafted, humanized or fully human. In another embodiment, theantibody or antigen-binding fragment thereof comprises one or more, twoor more, three or more, four or more, five or more, or all six of theheavy and light chain complimentarity determining regions (CDRs)including a) a heavy chain CDR1 having the amino acid sequence of SEQ IDNO: 9; b) a heavy chain CDR2 having the amino acid sequence of SEQ IDNO: 10; c) a heavy chain CDR3 having the amino acid sequence of SEQ IDNO: 11; d) a light chain CDR1 having the amino acid sequence of SEQ IDNO: 14; e) a light chain CDR2 having the amino acid sequence of SEQ IDNO: 15; and f) a light chain CDR3 having the amino acid sequence of SEQID NO: 16. The antibody or antigen-binding fragment thereof encompassesthe antibody produced, for example, by the hybridoma clone TW7-28G11.The antibody or antigen-binding fragment thereof can also encompass theantibody produced, for example, by any of the other anti-LAP hybridomaclones described herein. While unconjugated antibody can be effective,in one embodiment, the LAP-binding agent can be conjugated to acytotoxic or chemotherapeutic agent or drug.

It was also discovered that markers of memory T cells are up-regulatedfollowing treatment of tumors using a LAP-binding agent. Thus, alsodescribed herein is a method of promoting the formation of memory Tcells specific for an antigen of interest in a subject in need thereof,the method comprising administering a LAP-binding agent and the antigenof interest to the subject. In one embodiment, treatment with aLAP-binding agent results in increased CD44+ and/or increased IL7R+ Tcells. It is contemplated that this approach can provide benefit notonly in promoting and maintaining memory for a response to tumorantigen, but also for promoting and maintaining memory for a response toan infectious pathogen. The antigen of interest, which can be a purifiedantigen or a more crude antigen preparation such as a whole tumorantigen preparation, can be administered on its own, with an adjuvant,or in the form of a dendritic cell vaccine. In this aspect, as in othersdescribed herein, the LAP-binding agent administered can include, forexample, an antibody or antigen-binding fragment thereof. In oneembodiment, the antibody can be a monoclonal antibody or antigen-bindingfragment thereof. In another embodiment, the antibody or antigen-bindingfragment thereof can be chimeric, CDR-grafted, humanized or fully human.In another embodiment, the antibody or antigen-binding fragment thereofcomprises one or more, two or more, three or more, four or more, five ormore, or all six of the heavy and light chain complimentaritydetermining regions (CDRs) including a) a heavy chain CDR1 having theamino acid sequence of SEQ ID NO: 9; b) a heavy chain CDR2 having theamino acid sequence of SEQ ID NO: 10; c) a heavy chain CDR3 having theamino acid sequence of SEQ ID NO: 11; d) a light chain CDR1 having theamino acid sequence of SEQ ID NO: 14; e) a light chain CDR2 having theamino acid sequence of SEQ ID NO: 15; and f) a light chain CDR3 havingthe amino acid sequence of SEQ ID NO: 16. The antibody orantigen-binding fragment thereof encompasses the antibody produced, forexample, by the hybridoma clone TW7-28G11. The antibody orantigen-binding fragment thereof can also encompass the antibodyproduced, for example, by any of the other anti-LAP hybridoma clonesdescribed herein. While unconjugated antibody can be effective, in oneembodiment, the LAP-binding agent can be conjugated to a cytotoxic orchemotherapeutic agent or drug.

Also described herein is the use of a LAP-binding agent for:

the treatment of a disease or disorder characterized by or involving anundesirable number or activity of LAP+ T regulatory cells;

the treatment of cancer by decreasing the number or activity oftumor-infiltrated immunosuppressive T cells in a tumor, the usecomprising administering a LAP-binding agent to a subject with a tumorcomprising tumor-infiltrated immunosuppressive T cells, whereby thenumber or activity of such cells is decreased;

the treatment of cancer by increasing tumor-specific immunity, the usecomprising administering a therapeutically effective amount of aLAP-binding agent to a subject in need thereof;

the treatment of a cancer or tumor where LAP expression and/or activityis associated with suppression of cancer- or tumor-specific immunity,the use comprising administering a therapeutically effective amount of aLAP-binding agent to a subject in need thereof;

the treatment of a cancer or tumor by increasing the number of CD8+cytotoxic T cells in a tumor, the use comprising administering, to asubject with a tumor, a LAP-binding agent;

the treatment of a cancer or tumor by increasing peripheral CD4+ T cellsexpressing IFNγ in a subject in need thereof, the use comprisingadministering a LAP-binding agent to the subject;

the treatment of a cancer or tumor by increasing peripheral CD8+ T cellsexpressing granzyme B in a subject in need thereof, the use comprisingadministering a LAP-binding agent to the subject;

the treatment of a cancer or tumor by decreasing the number of FoxP3+regulatory T cells in a tumor, the use comprising administering aLAP-binding agent to the subject;

the treatment of a cancer or tumor by inhibiting expression of animmunosuppressive factor by CD8+ and/or CD4+ T cells in a tumor, the usecomprising administering a LAP-binding agent to a subject with a tumor;

promoting an anti-tumor immune response, the use comprising vaccinatinga subject in need of treatment for a tumor with a tumor antigen andadministering a LAP-binding agent to the subject;

treating cancer that is refractory to treatment with an immunecheckpoint inhibitor, the use comprising administering to a subjecthaving such cancer a LAP-binding agent;

treating cancer, the use comprising analyzing a tumor sample from asubject to determine the presence of LAP+ T regulatory cells, and, ifLAP+ T regulatory cells are present, administering to the subject aLAP-binding agent, thereby promoting an anti-tumor immune response;

promoting the formation of memory T cells specific for an antigen ofinterest for the treatment of cancer or an infection in a subject, theuse comprising administering a LAP-binding agent and the antigen ofinterest to the subject.

In each of the aspects described herein, the LAP-binding agent can be,for example, one that specifically binds a LAP molecule having thesequence set forth in any one of SEQ ID NOs: 1-3.

In one embodiment of each of the aspects described herein, the antibodyor antigen-binding fragment thereof can be, for example, one that bindsa LAP ligand interaction site. The LAP ligand interaction site can be,for example, a site that interacts with mature TGFβ, a site thatinteracts with integrins, and/or a site that interacts with latent TGFβbinding protein (LTBP).

In one embodiment of each of the aspects described herein, theLAP-binding agent binds LAP complexed with TGF-β and inhibits release ofTGF-β from the complex.

In one embodiment of each of the aspects described herein, themonoclonal antibody is one produced by any one of the hybridoma clonesselected from TW4-9E7, TW4-5A8, TW4-3E5, TW4-4E5, TW4-12B12, TW4-13B12,TW4-1G12, TW4-3G5, TW4-2F8, TW4-6H10, TW4-1G2, TW4-1E1, TW4-16F4,TW4-8F10, TW4-3H6, TW4-2C9, TW7-16B4, TW7-28G11, TW7-7H4, and TW7-20B9.

In one embodiment of each of the aspects described herein, theLAP-binding agent is a small molecule inhibitor, agent, or compound.

In one embodiment of each of the aspects described herein, theLAP-binding agent is an RNA or DNA aptamer that binds or physicallyinteracts with LAP.

In one embodiment of each of the methods described herein, the subjecthas or has been diagnosed with cancer.

In one embodiment of each of the methods described herein, the subjecthas or has been diagnosed with a brain tumor, a melanoma, or colorectalcancer. In one embodiment, the brain tumor is a glioblastoma.

In one embodiment of each of the therapeutic methods described hereinthe method further comprises administering an anti-cancer therapy,chemotherapeutic or immunomodulatory agent to the subject. In oneembodiment, the immunomodulatory agent comprises an immune checkpointinhibitor. In one embodiment, the immune checkpoint inhibitor binds toone or more of the following: PD1, PDL1, PDL2, CTLA4, LAG3, TIM3, TIGITand/or CD103. In one embodiment, the immune checkpoint inhibitor is aPD1, PDL1, and/or PDL2 inhibitory agent selected from pembrolizumab;nivolumab; MK-3475; MPDL3280A; MEDI0680; MEDI4736; AMP-224; andMSB0010718C.

In one embodiment of each of the therapeutic methods described herein,the methods further comprise administering a chemotherapeutic agent tothe subject.

In one embodiment of each of the therapeutic methods described herein,the method further comprises administering a tumor or cancer antigen tothe subject. In one embodiment, the method comprises administering aLAP-binding agent concurrently or in combination with dendritic cell(DC) vaccination.

In one embodiment of each of the therapeutic methods described herein,the LAP-binding agent is an isolated antibody or antigen-bindingfragment thereof as described herein or a pharmaceutical compositioncomprising such an antibody or antigen-binding fragment thereof.

Definitions

Unless otherwise defined herein, scientific and technical terms used inconnection with the present application shall have the meanings that arecommonly understood by those of ordinary skill in the art to which thisdisclosure belongs. It should be understood that this invention is notlimited to the particular methodology, protocols, and reagents, etc.,described herein and as such can vary. The terminology used herein isfor the purpose of describing particular embodiments only, and is notintended to limit the scope of the present invention, which is definedsolely by the claims. Definitions of common terms in immunology, andmolecular biology can be found in The Merck Manual of Diagnosis andTherapy, 18th Edition, published by Merck Research Laboratories, 2006(ISBN 0-911910-18-2); Robert S. Porter et al. (eds.), The Encyclopediaof Molecular Biology, published by Blackwell Science Ltd., 1994 (ISBN0-632-02182-9); and Robert A. Meyers (ed.), Molecular Biology andBiotechnology: a Comprehensive Desk Reference, published by VCHPublishers, Inc., 1995 (ISBN 1-56081-569-8); Immunology by WernerLuttmann, published by Elsevier, 2006. Definitions of common terms inmolecular biology are found in Benjamin Lewin, Genes IX, published byJones & Bartlett Publishing, 2007 (ISBN-13: 9780763740634); Kendrew etal. (eds.), The Encyclopedia of Molecular Biology, published byBlackwell Science Ltd., 1994 (ISBN 0-632-02182-9); and Robert A. Meyers(ed.), Maniatis et al., Molecular Cloning: A Laboratory Manual, ColdSpring Harbor Laboratory Press, Cold Spring Harbor, N.Y., USA (1982);Sambrook et al., Molecular Cloning: A Laboratory Manual (2 ed.), ColdSpring Harbor Laboratory Press, Cold Spring Harbor, N.Y., USA (1989);Davis et al., Basic Methods in Molecular Biology, Elsevier SciencePublishing, Inc., New York, USA (1986); or Methods in Enzymology: Guideto Molecular Cloning Techniques Vol. 152, S. L. Berger and A. R. KimmerlEds., Academic Press Inc., San Diego, USA (1987); Current Protocols inMolecular Biology (CPMB) (Fred M. Ausubel, et al. ed., John Wiley andSons, Inc.), Current Protocols in Protein Science (CPPS) (John E.Coligan, et. al., ed., John Wiley and Sons, Inc.) and Current Protocolsin Immunology (CPI) (John E. Coligan, et. al., ed. John Wiley and Sons,Inc.), which are all incorporated by reference herein in theirentireties.

As used herein, the term “LAP binding agent” refers to a molecule oragent that specifically binds LAP and significantly modulates theinteraction between LAP and any of its ligands or molecules thatinteract with LAP and consequently modulates their resultant biologicalor functional activity in vitro, in situ, and/or in vivo, includingactivity of downstream pathways mediated by LAP signaling, such as, forexample, TGF-β release from the small latent complex or latent complex,LAP-mediated inhibition of immune responses and LAP-mediated inhibitionof anti-tumor immune responses. Exemplary LAP binding agentscontemplated for use in the various aspects and embodiments describedherein include, but are not limited to, antibodies or antigen-bindingfragments thereof that specifically bind to one or more amino acidresidues or epitopes on LAP involved in the binding and/or interactionsof LAP and TGF-β, including an epitope formed when TGF-β is bound toLAP, LAP and integrins, and/or LAP and LTBP, and/or modulate LAPhomodimerization and/or binding; small molecule agents that target orspecifically bind to one or more amino acid residues or epitopes on LAPinvolved in the binding and/or interactions of LAP and TGFβ, LAP andintegrins, and/or LAP and LTBP, and/or LAP and GARP, and/or modulate LAPhomodimerization and/or binding; and RNA or DNA aptamers that bind toone or more amino acid residues or epitopes on LAP involved in thebinding and/or interactions of LAP and TGFβ, LAP and integrins, and/orLAP and LTBP, and/or modulate LAP homodimerization and/or binding. Inpreferred embodiments of the aspects described herein, a LAP bindingagent specifically binds LAP and inhibits or blocks TGF-β release fromthe small latent complex or latent complex.

As used herein, a LAP binding agent has the ability to modulate theinteraction between LAP and TGF-β, LAP and integrins, and/or LAP andLTBP, and/or modulate LAP homodimerization and/or their resultantbiological or functional activity in vitro, in situ, and/or in vivo byat least 5%, at least 10%, at least 20%, at least 30%, at least 40%, atleast 50%, at least 60%, at least 70%, at least 80%, at least 90%, atleast 95%, at least 98%, at least 99%, or more, relative to theinteraction and/or activity in the absence of the LAP binding agent. Ata minimum, a LAP binding agent as described herein blocks tumor-inducedimmune suppression in a cancer model, such as a subcutaneous mouseglioma model, and leads to higher expression of IFNγ on CD4+ T cells,reduced numbers and/or activity of regulatory CD4+ T cells, increasednumbers and/or infiltration of cytotoxic CD8+ T cells to the tumor,decreased tumor size, and/or increased survival in said model.

“Modulating an interaction between LAP and TGF-β/integrins/latent TGF-βbinding protein/LAP,” or “impacting an interaction between LAP andTGF-β/integrins/latent TGF-β binding protein/LAP” as usedinterchangeably herein, generally means either modulating, i.e.,increasing or decreasing, the interaction between or binding of LAP andTGF-β/integrins/latent TGF-β binding protein/LAP by at least 5%, atleast 10%, at least 25%, at least 50%, at least 60%, at least 70%, atleast 80%, at least 90%, at least 95%, at least 98%, or more, comparedto the interaction between LAP and TGF-β/integrins/latent TGF-β bindingprotein/LAP under the same conditions but without the presence of a LAPbinding agent. In preferred embodiments of the aspects described herein,a LAP binding agent modulates the interaction between LAP and TGF-β,such that release of TGF-β from the small latent complex is inhibited orblocked, and/or reduces the number of and/or activity of regulatory CD4+and/or CD8+ T cells.

As used herein, “increasing tumor-specific immunity” refers to directlyincreasing or amplifying the immune response directed against a canceror a tumor and/or removing suppression of the immune response against acancer or a tumor, and includes, but is not limited to, for example,increasing the recognition of cancer-specific antigens; increasing thenumber and/or activity of tumour infiltrating lymphocytes (e.g., CD4 andCD8 T cells) and/or tumor-infiltrating innate immune cells, such asnatural killer cells, natural killer T cells, macrophages and dendriticcells to the tumor site; increasing or amplifying cytokine and/orchemokine production at the tumor/cancer site, such as IFNγ, CXCL10,CXCL9 and CXCL11, IL-17, IL-12; decreasing/suppressing immune inhibitorymolecules, such as LAG3 and PD1; decreasing/suppressing regulatory cellpopulations such as T regulatory cells, including Foxp3+CD4 T cells andCD103+CD8 T cells etc. In this context and others herein, “increasing”refers at a minimum to a statistically significant increase, preferablyat least 10% or more relative to a reference.

As used herein, the phrase “a cancer or tumor where LAP expressionand/or activity is associated with suppression of cancer- ortumor-specific immunity” refers to those cancers/tumors in whichexpression and/or activity of LAP has been determined to correlate witha suppression of the cancer or tumor-specific immunity. In other words,a cancer or tumor where expression and/or activity of LAP correlateswith decreased recognition of cancer-specific antigens; lack orreduction in the number and/or activity of tumour infiltratinglymphocytes (e.g., CD4 and CD8 T cells) and/or tumor-infiltrating innateimmune cells, such as natural killer cells, natural killer T cells,macrophages and dendritic cells to the tumor site; decreased or absentcytokine and/or chemokine production at the tumor/cancer site, such asIFNγ, CXCL10, CXCL9 and CXCL11, IL-17, IL-12; increased expression ofimmune inhibitory molecules, such as LAG3 and PD1; increased presence ofregulatory cell populations such as T regulatory cells, includingFoxp3+CD4 T cells and CD103+CD8 T cells, for example.

As used herein, antibodies or antigen-binding fragments thereof includemonoclonal, human, humanized or chimeric antibodies, single chainantibodies, Fab fragments, F(ab′) fragments, fragments produced by a Fabexpression library, and/or antigen-binding fragments of any of theabove. Antibodies also refer to immunoglobulin molecules andimmunologically active portions of immunoglobulin molecules, i.e.,molecules that contain antigen or target binding sites or“antigen-binding fragments.” The immunoglobulin molecules describedherein can be of any type (e.g., IgG, IgE, IgM, IgD, IgA and IgY), class(e.g., IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2) or subclass ofimmunoglobulin molecule, as is understood by one of skill in the art.

The terms “antibody fragment” or “antigen-binding fragment” include,without limitation: (i) the Fab fragment, having V_(L), C_(L), V_(H) andC_(H)1 domains; (ii) the Fab′ fragment, which is a Fab fragment havingone or more cysteine residues at the C-terminus of the C_(H)1 domain;(iii) the Fd fragment having V_(H) and C_(H)1 domains; (iv) the Fd′fragment having V_(H) and C_(H)1 domains and one or more cysteineresidues at the C-terminus of the CH1 domain; (v) the Fv fragment havingthe V_(L) and V_(H) domains of a single arm of an antibody; (vi) a dAbfragment (Ward et al., Nature 341, 544-546 (1989)) which consists of aV_(H) domain or a V_(L) domain; (vii) isolated CDR regions; (viii)F(ab′)₂ fragments, a bivalent fragment including two Fab′ fragmentslinked by a disulphide bridge at the hinge region; (ix) single chainantibody molecules (e.g. single chain Fv; scFv) (Bird et al., Science242:423-426 (1988); and Huston et al., PNAS (USA) 85:5879-5883 (1988));(x) “diabodies” with two antigen binding sites, comprising a heavy chainvariable domain (V_(H)) connected to a light chain variable domain(V_(L)) in the same polypeptide chain (see, e.g., EP 404,097; WO93/11161; and Hollinger et al., Proc. Natl. Acad. Sci. USA, 90:6444-6448(1993)); (xi) “linear antibodies” comprising a pair of tandem Fdsegments (V_(H)—C_(H)1-V_(H)-C_(H)1) which, together with complementarylight chain polypeptides, form a pair of antigen binding regions (Zapataet al. Protein Eng. 8(10):1057-1062 (1995); and U.S. Pat. No.5,641,870); and modified versions of any of the foregoing that retainantigen-binding activity (e.g., modified by the covalent attachment ofpolyalkylene glycol (e.g., polyethylene glycol, polypropylene glycol,polybutylene glycol) or other suitable polymer).

As used herein, an “epitope” can be formed both from contiguous aminoacids, or noncontiguous amino acids juxtaposed by tertiary folding of aprotein. Epitopes formed from contiguous amino acids are typicallyretained on exposure to denaturing solvents, whereas epitopes formed bytertiary folding are typically lost on treatment with denaturingsolvents. An epitope typically includes at least 3, and more usually, atleast 5, about 9, or about 8-10 amino acids in a unique spatialconformation. An “epitope” includes the unit of structure conventionallybound by an immunoglobulin V_(H)/V_(L) pair. Epitopes define the minimumbinding site for an antibody, and thus represent the target ofspecificity of an antibody. In the case of a single domain antibody, anepitope represents the unit of structure bound by a variable domain inisolation. The terms “antigenic determinant” and “epitope” can also beused interchangeably herein.

The terms “specificity,” “specifically binds,” or “specific for” refersto the number of different types of antigens or antigenic determinantsto which a particular antibody or antigen-binding fragment thereof canbind. Accordingly, an antibody or antigen-binding fragment thereof asdefined herein is said to be “specific for” a first target or antigencompared to a second target or antigen when it binds to the firstantigen with an affinity (as described herein, and suitably expressed,for example as a K_(D) value) that is at least 50 times, such as atleast 100 times, and preferably at least 1000 times, and up to 10,000times or more better than the affinity with which said amino acidsequence or polypeptide binds to another target or polypeptide.Preferably, when an antibody or antigen-binding fragment thereof is“specific for” a target or antigen, compared to another target orantigen, it can bind said target or antigen, but not the other target orantigen.

As used herein, “small molecule inhibitors” include, but are not limitedto, small peptides or peptide-like molecules, soluble peptides, andsynthetic non-peptidyl organic or inorganic compounds. A small moleculeinhibitor or antagonist can have a molecular weight of any of about 100to about 20,000 daltons (Da), about 500 to about 15,000 Da, about 1000to about 10,000 Da

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-1E demonstrate LAP expression on immune cells in GBM.Mononuclear cells were isolated following percoll gradient separationfrom intracranial GBM. The levels of surface LAP expression weredetermined on myeloid cells (FIG. 1A), γδ T cells (FIG. 1B), and CD4 Tcells (FIG. 1C). Coexpression of LAP and FoxP3 was examined on CD4 Tcells in GBM (FIG. 1D). FIG. 1E. Expression of LAP on γδ T cells in thespleen of GBM mice. *p<0.05

FIGS. 2A-2D demonstrate that LAP+γδ T cells exhibit immune suppressiveproperties. Expression of inflammatory cytokines was analyzed on LAP−and LAP+γδ T cells in naïve mice by qRT-PCR (FIG. 2A) and flow cytometry(FIG. 2B). LAP+γδ T cells suppress T cell proliferation (FIG. 2C) andinduce FoxP3 expression (FIG. 2D) in naïve mice.

FIG. 3A-3B demonstrate induction of LAP expression on γδ T cells byglioma. LAP−γδ T cells were grown alone or co-cultured with GL261 gliomacells. Two and three days later, LAP expression was analyzed on γδ Tcells. Representative results for both time points (FIG. 3A) andstatistical analysis for three days incubation (FIG. 3B) are shown.*p<0.05

FIGS. 4A-4B demonstrate that Anti-LAP treatment skews the immune systemtowards pro-inflammatory responses. Naïve mice were treated withanti-LAP or IC antibodies. T cells were isolated from spleen andmesenteric lymph nodes (MLN) and T cell proliferation measured (FIG.4A). The isolated T cells were activated and cytokine secretion todetermine the potential of the cells to produce IFN-γ, IL17 and IL-2 wasestimated by ELISA (FIG. 4B).

FIGS. 5A-5K demonstrate that Anti-LAP treatment eliminates sub-cutaneousglioma growth and activates the immune system. GL261 glioma cells wereimplanted in the flanks of C57BL/6 mice and treated with anti-LAP orisotype-matched control (IC) antibodies. Following anti-LAP treatmenttumors shrunk (FIGS. 5A and 5B), peripheral Th1 responses increased(FIG. 5C), regulatory T cells decreased (FIGS. 5D-5F, 5K), CTL responseswere up-regulated (FIGS. 5G-5J). *p<0.05, **p<0.01, ****p<0.0001

FIG. 6 demonstrates that LAP Expression is Reduced on T Cell Subsets inAnti-LAP Treated Melanoma-Bearing Mice.

FIG. 7 demonstrates that CD4+ T Cells Exhibit Pro-Inflammatory Phenotypein Anti-LAP Treated Melanoma-Bearing Mice.

FIG. 8 demonstrates that CD8+ T Cells Exhibit Pro-Inflammatory Phenotypein Anti-LAP Treated Melanoma-Bearing Mice.

FIG. 9 demonstrates that NK Cells Exhibit Pro-Inflammatory Phenotype inAnti-LAP Treated Melanoma-Bearing Mice.

FIG. 10 demonstrates that Immune Cells isolated from LNs of Anti-LAPTreated Mice Proliferate Better. Proliferation of inguinal lymph nodecells of OVA-melanoma tumor bearing mice after 3 days of in vitrostimulation with 100 μg/ml of OVA.

FIG. 11 demonstrates that immune Cells isolated from LNs of Anti-LAPTreated Mice Have Pro-Inflammatory Profile. Cytokine production ofinguinal lymph node cells (by ELISA) of OVA-melanoma tumor bearing miceafter 3 days of in vitro stimulation with 100 μg/ml of OVA.

FIG. 12 demonstrates LAP Expression on CD4+ T Cells.

FIG. 13 demonstrates LAP Expression on CD16+CD14+.

FIG. 14 demonstrates LAP Expression on CD11b+CD14+CD16−—(ClassicalMonocytes, Resemble Ly6C−-hi).

FIG. 15 demonstrates LAP Expression on CD11b+CD14+CD16−—(ClassicalMonocytes, Resemble Ly6C−-hi).

FIG. 16 demonstrates LAP Expression on Lin-CD11c+(mDCs).

FIG. 17 demonstrates Gating for Lin-CD11c−CD123+(pDCs).

FIG. 18 demonstrates LAP Expression on Lin-CD11c−CD123+(pDCs).

FIG. 19 depicts LAP expression on CD4+ T Cells in spleen.

FIG. 20 demonstrates IFN-γ expression is higher on CD4+ T cells inspleen following anti-LAP treatment.

FIG. 21 demonstrates the Number of Regulatory CD4+ T Cells is Reduced inSpleen following anti-LAP treatment.

FIG. 22 demonstrates CD103 Expression is Decreased on CD4+ T Cells inSpleen following anti-LAP treatment.

FIG. 23 demonstrates LAP Expression on CD8+ T Cells in Spleen followinganti-LAP treatment.

FIG. 24 demonstrates Increase in Cytotoxic Phenotype of CD8+ T Cells inSpleen following anti-LAP treatment.

FIG. 25 demonstrates IFN-γ Expression on CD8+ T Cells is Higher inSpleen following anti-LAP treatment.

FIG. 26 demonstrates CD103 Expression is Lower on CD8+ T Cells in Spleenfollowing anti-LAP treatment.

FIG. 27 demonstrates Proportion of T Cell Subsets in Draining lymphnodes (LNs) following anti-LAP treatment.

FIG. 28 demonstrates CD103 Expression is Lower on CD8+ T Cells in LNfollowing anti-LAP treatment.

FIG. 29 demonstrates MHC Class II Expression is Increased on CD11c andCD11b Cells in Spleen following anti-LAP treatment.

FIG. 30 demonstrates LAP Expression on Myeloid Cells in Spleen (NaïveMice).

FIG. 31 demonstrates CD103 is Mainly Expressed by CD11b−Hi/CD11c−Lo(Naïve Mice).

FIG. 32 demonstrates Anti-LAP (16B4) Treatment Leads to Changes in theRatio of CD11c−Lo and CD11c−Hi subsets in spleen in a subcutaneous GL261GBM model.

FIG. 33 demonstrates CD103 Expression on CD11b−Hi/CD11c−Lo Cells isReduced by Anti-LAP in the Spleen in a subcutaneous GL261 GBM model.

FIG. 34 demonstrates CD103 Expression on CD11b−Hi/CD11c−Lo Cells isReduced by Anti-LAP in the Spleen in a subcutaneous GL261 GBM model.

FIG. 35 demonstrates PD-L1 Expression on CD11b−Hi/CD11c−Lo Cells isReduced by Anti-LAP in the Spleen in a subcutaneous GL261 GBM model.

FIG. 36 demonstrates LAP Expression on Myeloid Cells in Spleen in GBMMice in a subcutaneous GL261 GBM model.

FIG. 37 demonstrates LAP Expression on CD4+ and CD8+ T Cells in Tumor asubcutaneous GL261 GBM model.

FIG. 38 demonstrates LAP Expression on CD4+ T Cells in vivo.

FIG. 39 demonstrates CD4+LAP+ T Cells are Down-regulated FollowingAnti-LAP Treatment in Spleen.

FIGS. 40A-40B demonstrates Anti-LAP Antibodies Mediate ADCP and CDC.

FIG. 41 demonstrates Accumulation of CD8+ T Lymphocytes in GBM FollowingAnti-LAP Treatment.

FIG. 42 demonstrates Decrease in CD4+FoxP3+ T Cells in GBM FollowingAnti-LAP Treatment.

FIG. 43 demonstrates Decrease in LAG+CD4+ T Cells in GBM FollowingAnti-LAP Treatment.

FIG. 44 demonstrates Decrease in LAG+CD8+ T Cells in GBM FollowingAnti-LAP Treatment.

FIG. 45 demonstrates Decrease in PD1+ T Cells in GBM Following Anti-LAPTreatment.

FIG. 46 demonstrates Decrease in PD-L1+ T Cells in GBM FollowingAnti-LAP Treatment.

FIG. 47 demonstrates Decrease in CD103+ T Cells in GBM FollowingAnti-LAP Treatment.

FIG. 48 demonstrates Decreased Numbers of CD103 on CD4+ T Cells inSpleen.

FIG. 49 demonstrates Decreased Numbers of CD103 on CD8+ T Cells inSpleen and LNs.

FIG. 50 demonstrates treatment with anti-LAP in B16-OVA bearing miceleads to a better T cell response to OVA stimulation.

FIG. 51 depicts a sequence alignment and comparison between all humanand mouse LAP isoforms.

FIG. 52 depicts a sequence alignment and comparison between all humanLAP isoforms.

FIG. 53 depicts a sequence alignment and comparison between all mouseLAP isoforms.

FIG. 54 depicts a sequence alignment and comparison between all humanand mouse proTGF-β isoforms. SEQ ID NOs: 25-30 are disclosed in order oftheir appearance.

FIGS. 55A-55N depict therapeutic effects of anti-LAP antibodies incancer models. FIGS. 55A, 55B: melanoma, B16; FIGS. 55C-55F:intracranial GBM, FIGS. 55G, 55H: subcutaneous glioblastoma, GL261;FIGS. 55I-55N colorectal carcinoma (CRC) (FIGS. 55I-55K: AOM/DSS CRC,FIGS. 55L-55N: subcutaneous CRC). Mice were treated with TW7-28G11:FIGS. 55A, 55B, 55G, 55I-55N; and 16B4: FIGS. 55C-55F, 55H.

FIGS. 56A-56B depict effects of anti-LAP antibodies on adaptive immuneresponses using a melanoma tumor model. Effects in the intratumoral(FIG. 56A) and peripheral (FIG. 56B) immune responses are shown. Micewere treated with TW7-28G11.

FIGS. 57A-57J depict effects of anti-LAP antibodies on innate immuneresponses in the spleen. FIGS. 57A, 57B show accumulation ofCD11b−int/CD11c−hi cells and decrease in CD11b−hi/CD11c−int in thespleen after anti-LAP treatment. Expression of CD103 and PD-L1 isdecreased with anti-LAP treatment (FIG. 57C). LAP is mainly expressed onCD11b−hi cells (FIG. 57D). CD11b−hi cells express increased levels ofimmunosuppressive cytokines, TGF-b and IL-10, and reduced expression ofa proinflammatory cytokine, IL-12 as compared to CD11b−int (FIG. 57E).Co-culture of CD11b−int with CD8+ T cells promotes the expression ofproinflammatory cytokines (FIG. 57F). Expression of antigen-presentationmarkers, MHCII (FIG. 87G) and CD86 (FIG. 57H) is higher on CD11b−intthan on CD11b−hi. CD11b−hi cells are not able to support CD8+ T cellgrowth in vitro (FIG. 57I). Anti-LAP treatment leads to the accumulationof NK cells expressing IFN-g (FIG. 57J). Mice were treated withTW7-16B4.

FIGS. 58A-58D demonstrate that anti-LAP antibodies deplete suppressiveCD4+ T cells. FIG. 58A shows that anti-LAP treatment reduces the numberof LAP+CD4+ T cells in vivo. Melanoma (B16)-bearing mice were treatedwith TW7-28G11 clone of anti-LAP and counted with non-competing TW7-16B4clone. Mice were treated with TW7-28G11. FIG. 58B shows that LAP+CD4+ Tcells express increased levels of suppression markers. FIG. 58Cdemonstrates that LAP+CD4+ T cells poses suppressive abilities. FIG. 58Dshows that anti-LAP diminishes the suppressive abilities of LAP+CD4+ Tcells.

FIGS. 59A-59E demonstrate that anti-LAP antibodies reduce the numbers ofsuppressive CD103+CD8+ T cells in spleen and draining lymph nodes (dLNs,FIG. 59A). CD8+ but not CD4+ T cells are required for the therapeuticeffect of anti-LAP (FIG. 59B). Anti-LAP antibodies reduce thesuppressive abilities of CD103+CD8+ T cells in vitro (FIG. 59C).Adoptive transfer of CD103+CD8+ T cells to CD8KO mice abolishes thetherapeutic effect of anti-LAP thus demonstrating their suppressiveeffect in vivo (FIG. 59D). CD103 expression is preserved on CD8+ T cellsater their adoptive transfer and CD103+CD8+ T express reduced levels ofactivation markers (FIG. 89E). Mice were treated with TW7-28G11.

FIGS. 60A-60C demonstrate that anti-LAP treatment combined withdendritic cell (DC) vaccination protects mice from GBM. Mice wereprevaccinated with ovalbumin loaded DCs and treated with anti-LAP. Aweek later, the mice were implanted with GL261-OVA glioma cellsintracranially and mice survival and tumor growth were followedthereafter. FIGS. 60D-60F demonstrate increased accumulation oftumor-specific CD8+ memory cells after anti-LAP treatment. Mice weretreated with the TW7-16B4 anti-LAP clone.

FIG. 61 demonstrates that anti-LAP treatment combined with dendriticcell vaccination improves treatment of B16 melanoma. Mice wereprevaccinated with ovalbumin loaded DCs and treated with TW7-28G11. Aweek later, the mice were implanted with B16-OVA melanoma and tumorgrowth was measured. Naïve (non-vaccinated mice) were used as a controlfor vaccination.

FIG. 62 demonstrates that high expression of TGF-β1/LAP and otherLAP-related mRNAs correlate with better GBM, melanoma and CRC patientssurvival. Relationship between cancer patient survival and mRNAexpression in tumors based on The Tumor Cancer Genome Atlas (TCGA) data.

FIG. 63 depicts survival of other cancer patients (AML, bladdercarcinoma, stomach adenocarcinoma) expressing low levels ofLAP-associated genes (TCGA).

FIG. 64 depicts an exemplary screen for anti-LAP antibodies by theirinhibition of TGF-β Release. Different clones of anti-LAP were tested bytheir treatment of P3U1 cells expressing a human TGF-β and measuring thelevel of secreted active/free TGF-β (non-acidified conditions) in theculture medium by ELISA.

FIG. 65 demonstrates that anti-LAP treatment does not affect plateletcounts and activity. Mice were treated with TW7-28G11 clone of anti-LAP(250 ug/mouse) and analysed 3 days later (n=3).

FIG. 66 depicts similarity between mouse and human proTGF-β proteinsequences.

FIG. 67 demonstrates that markers of memory T Cells are up-regulated inGBM following anti-LAP treatment.

DETAILED DESCRIPTION

Compositions and methods are provided that relate to the discoveriesdescribed herein that tumor growth is lower and mice survive longer whentreated with anti-LAP antibodies, and that the anti-LAP antibodiesdescribed herein block TGF-β release and deplete suppressive regulatoryT cell populations, including CD4+LAP+ T cells and CD8+CD103+ T cells.Anti-LAP antibodies were tested in various cancer models, including aglioblastoma model, a melanoma model, and a colorectal cancer model, andsimilar intra-tumor and peripheral immune effects were observed, asdescribed herein. Thus, as demonstrated herein, treatment with ananti-LAP antibody that acts, in part, by blocking TGF-β release anddepleting suppressive CD4+ T cells, strongly influences systemic andintra-tumor immune responses by activating both innate and adaptiveimmunity and overcomes the mechanisms suppressing tumor-specificimmunity.

LAP and LAP Binding Agents

LAP and TGF-β are translated as one precursor polypeptide that undergoesintracellular cleavage by furin, resulting in the separation of theN-terminal LAP protein portion from TGF-β. TGF-β is immediatelyreassembled non-covalently with LAP by forming a small latent complex(SLC) that retains TGF-β in its inactive form deposited on the cellsurface bound to GARP receptor or embedded into the extracellular matrixfollowing SLC binding to the latent TGF-β-binding protein 1 (LTBP-1).TGF-β must be released from its latent form by a specific signal toinitiate signal transduction. This mechanism is believed to allowimmediate availability and fast release of the active cytokine whenneeded and explains why TGF-β, different from other cytokines, isconstitutively expressed but silent in many tissues.

The transforming growth factor beta (TGFβ) protein family consists ofthree distinct isoforms found in mammals (TGFβ1, TGFβ2, and TGFβ3). TheTGFβ proteins activate and regulate multiple gene responses thatinfluence disease states, including cell proliferative, inflammatory,and cardiovascular conditions. TGFβ is a multifunctional cytokineoriginally named for its ability to transform normal fibroblasts tocells capable of anchorage—independent growth. The TGFβ molecules areproduced primarily by hematopoietic and tumor cells and can regulate,i.e., stimulate or inhibit, the growth and differentiation of cells froma variety of both normal and neoplastic tissue origins (Sporn et al.,Science, 233: 532 (1986)), and stimulate the formation and expansion ofvarious stromal cells.

The TGFβs are known to be involved in many proliferative andnon-proliferative cellular processes such as cell proliferation anddifferentiation, embryonic development, extracellular matrix formation,bone development, wound healing, hematopoiesis, and immune andinflammatory responses. See e.g., Pircher et al, Biochem. Biophys. Res.Commun., 136: 30-37 (1986); Wakefield et al., Growth Factors, 1: 203-218(1989); Roberts and Sporn, pp 419-472 in Handbook of ExperimentalPharmacology cds M. B. Sporn & A. B. Roberts (Springer, Heidelberg,1990); Massague et al., Annual Rev. Cell Biol., 6: 597-646 (1990);Singer and Clark, New Eng. J. Med., 341: 738-745 (1999). Also, TGFβ isused in the treatment and prevention of diseases of the intestinalmucosa (WO 2001/24813). TGFβ is also known to have strongimmunosuppressuve effects on various immunologic cell types, includingcytotoxic T lymphocyte (CTL) inhibition (Ranges et al., J. Exp. Med.,166: 991, 1987), Espevik et al., J. Immunol., 140: 2312, 1988),depressed B cell lymphopoiesis and kappa light-chain expression (Lee etal., J. Exp. Med., 166: 1290, 1987), negative regulation ofhematopoiesis (Sing et al., Blood, 72: 1504, 1988), down-regulation ofHLA-DR expression on tumor cells (Czarniecki et al., J. Immunol., 140:4217, 1988), and inhibition of the proliferation of antigen-activated Blymphocytes in response to B-cell growth factor (Petit-Koskas et al.,Eur. J. Immunol., 18: 111, 1988). See also U.S. Pat. No. 7,527,791.

TGF-β isoform expression in cancer is complex and variable withdifferent combinations of TGFβ isoforms having different roles inparticular cancers. See e.g., U.S. Pat. No. 7,927,593. For example,TGF-β1 and TGF-β3 may play a greater role in ovarian cancer and itsprogression than TGFβ2; while TGF-β1 and TGF-β2 expression is greater inhigher grade chondrosarcoma tumors than TGF-β3. In human breast cancer,TGF-β1 and TGF-β3 are highly expressed, with TGF-β3 expression appearingto correlate with overall survival—patients with node metastasis andpositive TGFβ3 expression have poor prognostic outcomes. However, incolon cancer, TGF-β1 and TGF-β2 are more highly expressed than TGF-β3and are present at greater circulating levels than in cancer-freeindividuals. In gliomas, TGF-β2 is important for cell migration.

As used herein, “Latency associated peptide” or “LAP” refers: to theamino-terminal domain of the human TGF-β1 precursor peptide having theamino acid sequenceLSTCKTIDMELVKRKRIEAIRGQILSKLRLASPPSQGEVPPGPLPEAVLALYNSTRDRVAGESAEPEPEPEADYYAKEVTRVLMVETHNEIYDKFKQSTHSIYMFFNTSELREAVPEPVLLSRAELRLLRLKLKVEQHVELYQKYSNNSWRYLSNRLLAPSDSPEWLSFDVTGVVRQWLSRGGEIEGFRLSAHCSCDSRDNTLQVDINGFTTGRRGDLATIHGMNRPFLLLMATPLERAQHLQSSRHRR (SEQ ID NO: 1),as described by, e.g., amino acids 30-278 of NP_000651.3; to theamino-terminal domain of the human TGF-β2 precursor peptide having theamino acid sequenceLSTCSTLDMDQFMRKRIEAIRGQILSKLKLTSPPEDYPEPEEVPPEVISIYNSTRDLLQEKASRRAAACERERSDEEYYAKEVYKIDMPPFFPSENAIPPTFYRPYFRIVRFDVSAMEKNASNLVKAEFRVFRLQNPKARVPEQRIELYQILKSKDLTSPTQRYIDSKVVKTRAEGEWLSFDVTDAVHEWLHHKDRNLGFKISLHCPCCTFVPSNNYIIPNKSEELEARFAGIDGTSTYTSGDQKTIKSTRKKNSGKTPHLLLMLLPSYRLESQQTNRRKKR (SEQ ID NO: 2), as described by, e.g., amino acids21-302 of NP_001129071.1; to the amino-terminal domain of the humanTGF-β3 precursor peptide having the amino acid sequenceLSTCTTLDFGHIKKKRVEAIRGQILSKLRLTSPPEPTVMTHVPYQVLALYNSTRELLEEMHGEREEGCTQENTESEYYAKEIHKFDMIQGLAEHNELAVCPKGITSKVFRFNVSSVEKNRTNLFRAEFRVLRVPNPSSKRNEQRIELFQILRPDEHIAKQRYIGGKNLPTRGTAEWLSFDVTDTVREWLLRRESNLGLEISIHCPCHTFQPNGDILENIHEVMEIKFKGVDNEDDHGRGDLGRLKKQKDHHNPHLILMMIPPHRLDNPGQGGQRKKR (SEQ ID NO: 3), as described by, e.g., amino acids24-300 of NP_003230.1; to the amino-terminal domain of the mouse TGF-β1precursor peptide having the amino acid sequenceLSTCKTIDMELVKRKRIEAIRGQILSKLRLASPPSQGEVPPGPLPEAVLALYNSTRDRVAGESADPEPEPEADYYAKEVTRVLMVDRNNAIYEKTKDISHSIYMFFNTSDIREAVPEPPLLSRAELRLQRLKSSVEQHVELYQKYSNNSWRYLGNRLLTPTDTPEWLSFDVTGVVRQWLNQGDGIQGFRFSAHCSCDSKDNKLHVEINGISPKRRGDLGTIHDMNRPFLLLMATPLERAQHLHSSRHRR (SEQ ID NO: 4),as described by, e.g., amino acids 30-278 of NP_035707.1; to theamino-terminal domain of the mouse TGF-β2 precursor peptide having theamino acid sequenceLSTCSTLDMDQFMRKRIEAIRGQILSKLKLTSPPEDYPEPDEVPPEVISIYNSTRDLLQEKASRRAAACERERSDEEYYAKEVYKIDMPSHLPSENAIPPTFYRPYFRIVRFDVSTMEKNASNLVKAEFRVFRLQNPKARVAEQRIELYQILKSKDLTSPTQRYIDSKVVKTRAEGEWLSFDVTDAVQEWLHHKDRNLGFKISLHCPCCTFVPSNNYIIPNKSEELEARFAGIDGTSTYASGDQKTIKSTRKKTSGKTPHLLLMLLPSYRLESQQSSRRKKR (SEQ ID NO: 5), as described by, e.g., aminoacids 21-302 of NP_033393.2; to the amino-terminal domain of the mouseTGF-β3 precursor peptide having the amino acid sequenceLSTCTTLDFGHIKKKRVEAIRGQILSKLRLTSPPEPSVMTHVPYQVLALYNSTRELLEEMHGEREEGCTQETSESEYYAKEIHKFDMIQGLAEHNELAVCPKGITSKVFRFNVSSVEKNGTNLFRAEFRVLRVPNPSSKRTEQRIELFQILRPDEHIAKQRYIGGKNLPTRGTAEWLSFDVTDTVREWLLRRESNLGLEISIHCPCHTFQPNGDILENVHEVMEIKFKGVDNEDDHGRGDLGRLKKQKDHHNPHLILMMIPPHRLDSPGQGSQRKKR (SEQ ID NO: 6), as described by, e.g., amino acids24-298 of NP_033394.2; together with any other naturally occurringallelic, splice variants, and processed forms thereof. The term “LAP” isalso used, in some embodiments, to refer to truncated forms or fragmentsof the LAP polypeptide. Reference to any such forms of LAP can beidentified in the application, e.g., by “LAP(215-217).” Specificresidues of LAP can be referred to as, for example, “LAP (194),” “aminoacid 194 of SEQ ID NO: 1,” or “Cys 194 of LAP of SEQ ID NO: 1.”

In some embodiments, LAP can exist as a homodimer of LAP molecules.Sequences of LAP polypeptides are known for a number of species, e.g.human and mouse LAP. Agents that physically interact with, bind to, orsterically occlude ligand binding to their interaction sites can be usedto inhibit LAP activity.

LAP contains important residues necessary for the interaction withbinding partners, e.g., TGFβ. Cysteines at positions 194 and 196 of SEQID NOs: 1 and 4, 206 and 208 of SEQ ID NOs: 2 and 5, and 204 and 206 ofSEQ ID NOs: 3 and 6 are important in the intermolecular disulphide bondbetween two LAPs. Their mutation to serine renders the molecule “active”(Sanderson et al., Proc. Natl. Acad. Sci. USA, 92, 2572-2576 (1995);Brunner et al, Mol. Endocrinol. 6, 1691-1700 (1992); Brunner et al, J.Biol. Chem, 264, 13660-13664 (1989); which are incorporated by referenceherein in their entireties). The RGD/SGD motif at positions 215-217 ofSEQ ID NOs: 1 and 4, 241-243 of SEQ ID NOs: 2 and 5, and 238-240 of SEQID NOs: 3 and 6 facilitates the interaction with integrins (Munger etal, Mol Biol Cell, 9:2627-2638 (1998; DerynckR, TIBS, 19, 548-553(1994); which are incorporated by reference herein in their entireties).Cysteine at position 4 of SEQ ID NOs: 1-6 is important for thedisulphide bridge with the third cysteine-rich repeat of LTBP (Saharinenet al. The EMBO Journal, 15, 245-253 (1996)). Nucleic acid encoding TGFβis described in U.S. Pat. No. 5,801,231. The foregoing references areincorporated by reference herein in their entireties.

Provided herein are compositions and methods based, in part, on thediscovery that tumor growth is lower and mice survive longer whentreated with anti-LAP antibodies, and that the effects of the anti-LAPantibodies described herein were based, in part, on their ability toinhibit the release of TGF-β from the small latent complex (SLC)comprising LAP that retains TGF-β in its inactive form, and/or to reducethe number of regulatory CD4+ T cells. As shown herein, anti-LAPantibody treatment also affected both systemic and intra-tumor immunityas follows. Tumors were infiltrated by increased numbers of cytotoxicCD8+ T cells and intra-tumor Foxp3 Tregs were decreased. CD4+ and CD8+intra-tumor T cells had decreased expression of PD-1, LAG3 and CD103. Inthe periphery, CD4+ and CD8+ T cells, expressing IFN-γ and granzyme B,were increased, respectively whereas CD103+ T cells were decreased.Finally, there were reduced numbers of tolerogenic dendritic cellsexpressing CD103 and PD-L1 whereas MHC II was elevated on splenicmyeloid cells. The anti-LAP antibodies described herein stronglyinfluence systemic and intra-tumor immune responses by activating bothinnate and adaptive immunity and overcome the mechanisms suppressingtumor-specific immunity. Without wishing to be bound or limited bytheory, this activity may involve sequestering active TGF-β bypreventing its release from the SLC and/or reducing the number ofregulatory CD4+ T cells. Given their demonstrated activities against arange of tumor types, anti-LAP antibodies as described herein can beused as a monotherapy or combined with other anti-tumor modalities, suchas, for example, anti-PD1 antibodies, other agents targeting tumorimmunosuppression and/or other anti-cancer therapies, and represent anovel immunotherapeutic approach for the treatment of cancers.

Accordingly, provided herein, in some aspects, are compositions andmethods to treat cancer and tumors where LAP expression and/or activityis associated with suppression of cancer- or tumor-specific immunity,comprising administering a therapeutically effective amount of a LAPbinding agent to a subject in need thereof. Such binding agents can beused to modulate the interaction between LAP and TGFβ, such that TGFβ isnot released from the small latent complex, and/or inhibit/blockinteraction between LAP and another LAP molecule, i.e., inhibit/blockhomodimerization. In particular, in preferred embodiments of the aspectsdescribed herein, such LAP binding agents can be used to inhibit orblock release of TGFβ from the small latent complex comprising LAP andmature TGFβ, thus sequestering mature TGFβ.

In some embodiments of the methods described herein, a LAP binding agentcan bind a LAP molecule having the sequence set forth in any one of SEQID NOs: 1-6. In some embodiments of the methods described herein, a LAPbinding agent can bind a LAP molecule having the sequence set forth inany one of SEQ ID NOs: 1-3. In some embodiments of the methods describedherein, a LAP binding agent can bind a conserved region shared betweenthe sequences set forth in any of SEQ ID NOs: 1-3. In some embodiments,a LAP binding agent can bind an epitope derived from any of SEQ ID NOs:1-6 and a LAP interacting protein, such as TGFβ. In some suchembodiments, where the LAP binding agent binds an epitope derived fromany of SEQ ID NOs: 1-6 and TGFβ, binding of the LAP binding agent to theepitope inhibits or blocks release of TGFβ from the small latentcomplex.

In some embodiments, a LAP binding agent for use in the compositions andmethods described herein can bind or physically interact with a LAPligand interaction site, e.g. a site that interacts with mature TGFβ, asite that interacts with integrins, and/or a site that interacts withLTBP. Non-limiting examples of such sites include R189 of SEQ ID NOs: 1and 4, R196 of SEQ ID NOs: 2 and 5, and R192 of SEQ ID NOs: 3 and 6(see, e.g. McGowan et al. The Journal of Clinical Endocrinology andMetabolism 2003 88:3321-6; which is incorporated by reference herein inits entirety). Accordingly, in some embodiments of the compositions andmethods described herein, a LAP binding agent binds or physicallyinteracts with R189 of SEQ ID NOs: 1 and 4, R196 of SEQ ID NOs: 2 and 5,and/or R192 of SEQ ID NOs: 3 and 6. In some embodiments of thecompositions and methods described herein, a LAP binding agent binds orphysically interacts with amino acids 215-217 of SEQ ID NOs: 1 and 4,amino acids 241-243 of SEQ ID NOs: 2 and 5, and/or amino acids 238-240of SEQ ID NOs: 3 and 6. In some embodiments of the methods describedherein, a LAP binding agent binds or physically interacts with Cys4 ofany of SEQ ID NOs: 1-6.

In some embodiments of the aspects described herein, a LAP binding agentfor use in the compositions and methods described herein can bind orinteract with a LAP homodimerization site, i.e., a site that interactswith another LAP molecule. Accordingly, in some embodiments of theaspects described herein, a LAP binding agent binds or physicallyinteracts with Cys194 and/or Cys196 of SEQ ID NOs: 1 and 4, Cys206and/or Cys208 of SEQ ID NOs: 2 and 5, and/or Cys204 and/or Cys206 of SEQID NOs: 3 and 6.

As used herein, the term “LAP binding agent” refers to a molecule oragent that specifically binds LAP and significantly modulates theinteraction between LAP and any of its ligands or molecules thatinteract with LAP and consequently modulates their resultant biologicalor functional activity in vitro, in situ, and/or in vivo, includingactivity of downstream pathways mediated by LAP signaling, such as, forexample, TGF-β release from the small latent complex or latent complex,LAP-mediated inhibition of immune responses and LAP-mediated inhibitionof anti-tumor immune responses. Exemplary LAP binding agentscontemplated for use in the various aspects and embodiments describedherein include, but are not limited to, antibodies or antigen-bindingfragments thereof that specifically bind to one or more amino acidresidues or epitopes on LAP involved in the binding and/or interactionsof LAP and TGF-β, LAP and integrins, and/or LAP and LTBP, and/ormodulate LAP homodimerization and/or binding; small molecule agents thattarget or specifically bind to one or more amino acid residues orepitopes on LAP involved in the binding and/or interactions of LAP andTGFβ, LAP and integrins, and/or LAP and LTBP, and/or modulate LAPhomodimerization and/or binding; and RNA or DNA aptamers that bind toone or more amino acid residues or epitopes on LAP involved in thebinding and/or interactions of LAP and TGFβ, LAP and integrins, and/orLAP and LTBP, and/or modulate LAP homodimerization and/or binding. Inpreferred embodiments of the aspects described herein, a LAP bindingagent specifically binds LAP and inhibits or blocks TGF-β release fromthe small latent complex or latent complex.

As used herein, a LAP binding agent has the ability to modulate theinteraction between LAP and TGF-β, LAP and integrins, and/or LAP andLTBP, and/or modulate LAP homodimerization and/or their resultantbiological or functional activity in vitro, in situ, and/or in vivo byat least 5%, at least 10%, at least 20%, at least 30%, at least 40%, atleast 50%, at least 60%, at least 70%, at least 80%, at least 90%, atleast 95%, at least 98%, at least 99%, or more, relative to theinteraction and/or activity in the absence of the LAP binding agent. Ata minimum, a LAP binding agent as described herein blocks tumor-inducedimmune suppression in a mouse cancer model, such as a subcutaneous mouseglioma model. This activity leads to higher expression of IFNγ on CD4+ Tcells, reduced numbers and/or activity of regulatory CD4+ T cells,increased numbers and/or infiltration of cytotoxic CD8+ T cells to thetumor, decreased tumor size, and/or increased survival in the mousesubcutaneous glioma model.

“Modulating an interaction between LAP and TGF-β/integrins/latent TGF-βbinding protein/LAP,” or “impacting an interaction between LAP andTGF-β/integrins/latent TGF-β binding protein/LAP” as usedinterchangeably herein, generally means either modulating, i.e.,increasing or decreasing, the interaction between or binding of LAP andTGF-β/integrins/latent TGF-β binding protein/LAP by at least 5%, atleast 10%, at least 25%, at least 50%, at least 60%, at least 70%, atleast 80%, at least 90%, at least 95%, at least 98%, or more, comparedto the interaction between LAP and TGF-β/integrins/latent TGF-β bindingprotein/LAP under the same conditions but without the presence of a LAPbinding agent as described herein. In preferred embodiments of theaspects described herein, a LAP binding agent modulates the interactionbetween LAP and TGF-β, such that release of TGF-β from the small latentcomplex is inhibited or blocked, and/or reduces the number of and/oractivity of regulatory CD4+ T cells.

Some LAP binding reagents, such as anti-LAP antibodies are known in theart. See, e.g., Ali et al. PLOS ONE 2008:e1914; which is incorporated byreference herein in its entirety. Further examples of anti-LAP antibodyreagents are described in U.S. Pat. No. 8,198,412 and U.S. PatentPublication No. 2008/0206219; which are incorporated by reference hereinin their entireties.

In some embodiments of the aspects described herein, an anti-LAPantibody or antigen-binding fragment thereof for use in the compositionsand methods described herein can bind or physically interact with a LAPligand interaction site, e.g., a site that interacts with mature TGF-β,a site that interacts with integrins, and/or a site that interacts withLTBP. In some embodiments of the aspects described herein, an anti-LAPantibody or antigen-binding fragment thereof for use in the compositionsand methods described herein binds or physically interacts with anepitope of LAP that exists when LAP is bound to latent TGF-β. In someembodiments of the aspects described herein, an anti-LAP antibody orantigen-binding fragment thereof for use in the compositions and methodsdescribed herein binds both mouse and human LAP.

In some embodiments of the aspects described herein, an anti-LAPantibody or antigen-binding fragment thereof binds or physicallyinteracts with R189 of SEQ ID NOs: 1 and 4, R196 of SEQ ID NOs: 2 and 5,and/or R192 of SEQ ID NOs: 3 and 6. In some embodiments of the aspectsdescribed herein, an anti-LAP antibody or antigen-binding fragmentthereof binds or physically interacts with amino acids 215-217 of SEQ IDNOs: 1 and 4, amino acids 241-243 of SEQ ID NOs: 2 and 5, and/or aminoacids 238-240 of SEQ ID NOs: 3 and 6. In some embodiments of the aspectsdescribed herein, an anti-LAP antibody or antigen-binding fragmentthereof binds or physically interacts with Cys4 of any of SEQ ID NOs:1-6.

In some embodiments of the aspects described herein, an anti-LAPantibody or antigen-binding fragment thereof for use in the compositionsand methods described herein can bind or physically interact with a LAPhomodimerization site, i.e., a site that interacts with another LAPmolecule. Accordingly, in some embodiments of the aspects describedherein, an anti-LAP antibody or antigen-binding fragment thereof bindsor physically interacts with Cys194 and/or Cys196 of SEQ ID NOs: 1 and4, Cys206 and/or Cys208 of SEQ ID NOs: 2 and 5, and/or Cys204 and/orCys206 of SEQ ID NOs: 3 and 6.

Antibodies or antigen-binding fragments thereof that are specific for orthat selectively bind LAP, suitable for use in the compositions and forpracticing the methods described herein are preferably monoclonal, andcan include, but are not limited to, human, humanized, CDR grafted, orchimeric antibodies, comprising single chain antibodies, Fab fragments,F(ab′) fragments, fragments produced by a Fab expression library, and/orbinding fragments of any of the above. Antibodies also refer toimmunoglobulin molecules and immunologically active portions ofimmunoglobulin molecules, i.e., molecules that contain antigen or targetbinding sites or “antigen-binding fragments.” The immunoglobulinmolecules described herein can be of any type (e.g., IgG, IgE, IgM, IgD,IgA and IgY), class (e.g., IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2) orsubclass of immunoglobulin molecule, as is understood by one of skill inthe art. The term “antibody” is intended to refer to immunoglobulinmolecules consisting of 4 polypeptide chains, two heavy (H) chains andtwo light (L) chains. The chains are usually linked to one another viadisulfide bonds. Each heavy chain is composed of a variable region ofsaid heavy chain (abbreviated here as HCVR or V_(H)) and a constantregion of said heavy chain. The heavy chain constant region consists ofthree domains CH1, CH2 and CH3. Each light chain is composed of avariable region of said light chain (abbreviated here as LCVR or V_(L))and a constant region of said light chain. The light chain constantregion consists of a CL domain The V_(H) and V_(L) regions can befurther divided into hypervariable regions referred to ascomplementarity-determining regions (CDRs) and interspersed withconserved regions referred to as framework regions (FR). Each V_(H) andV_(L) region thus consists of three CDRs and four FRs which are arrangedfrom the N terminus to the C terminus in the following order: FR1, CDR1,FR2, CDR2, FR3, CDR3, FR4. This structure is well-known to those skilledin the art.

As used herein, the term “CDR” refers to the complementarity determiningregion within antibody variable sequences. There are three CDRs in eachof the variable regions of the heavy chain and of the tight chain, whichare designated CDR 1, CDR2 and CDR3, for each of the variable regions.The term “CDR set” as used herein refers to a group of three CDRs thatoccur in a single variable region capable of binding the antigen. Theexact boundaries of these CDRs have been defined differently accordingto different systems. The system described by Kabat (Kabat et al,Sequences of Proteins of Immunological Interest (National Institutes ofHealth, Bethesda, Md. (1987) and (1991)) not only provides anunambiguous residue numbering system applicable to any variable regionof an antibody, but also provides precise residue boundaries definingthe three CDRs. These CDRs may be referred to as Kabat CDRs. Eachcomplementarity determining region may comprise amino acid residues froma “complementarity determining region” as defined by Kabat (i.e. aboutresidues 24-34 (L1), 50-56 (L2) and 89-97 (L3) in the light chainvariable domain and 31-35 (H1), 50-65 (H2) and 95-102 (H3) in the heavychain variable domain; Kabat et al., Sequences of Proteins ofImmunological Interest, 5th Ed. Public Health Service, NationalInstitutes of Health, Bethesda, Md. (1991)) and/or those residues from a“hypervariable loop” (i.e. about residues 26-32 (L1), 50-52 (L2) and91-96 (L3) in the light chain variable domain and 26-32 (H1), 53-55 (H2)and 96-101 (H3) in the heavy chain variable domain; Chothia and Lesk J.Mol. Biol. 196:901-917 (1987)). In some instances, a complementaritydetermining region can include amino acids from both a CDR regiondefined according to Kabat and a hypervariable loop. For example, theCDRH1 of the human heavy chain of antibody 4D5 includes amino acids 26to 35. Chothia and coworkers (Chothia & Lesk, J. Mol. Biol, 196:901-917(1987) and Chothia et al., Nature 342:877-883 (-1989)) found thatcertain sub-portions within Kabat CDRs adopt nearly identical peptidebackbone conformations, in spite of great diversity at the level ofamino acid sequence. These sub-portions were designated as L1, L2 and L3or H1, H2 and H3 where the “L” and the “H” designates the light chainand the heavy chains regions, respectively. These regions may bereferred to as Chothia CDRs, which have boundaries that overlap withKabat CDRs. Other boundaries defining CDRs overlapping with the KabatCDRs have been described by Padlan (FASEB). 9:133439 (1995)) andMacCallum (J Mot Biol 262(5):732-45 (1996)). Still other CDR boundarydefinitions may not strictly follow one of the above systems, but willnonetheless overlap with the Kabat CDRs, although they may be shortenedor lengthened in light of prediction or experimental findings thatparticular residues or groups of residues or even entire CDRs do notsignificantly impact antigen binding. The methods used herein mayutilize CDRs defined according to any of these systems, althoughpreferred embodiments use Kabat or Chothia defined CDRs. As used herein,“antibody variable domain” refers to the portions of the light and heavychains of antibody molecules that include amino acid sequences ofComplementarity Determining Regions (CDRs; ie., CDR1, CDR2, and CDR3),and Framework Regions (FRs). V_(H) refers to the variable domain of theheavy chain. V_(L) refers to the variable domain of the light chain.According to the methods used in this invention, the amino acidpositions assigned to CDRs and FRs may be defined according to Kabat(Sequences of Proteins of Immunological Interest (National Institutes ofHealth, Bethesda, Md., 1987 and 1991)) Amino acid numbering ofantibodies or antigen binding fragments is also according to that ofKabat.

Examples of antibody fragments encompassed by the terms antigen-bindingfragment or “antigen-binding moiety” as described herein include: (i)the Fab fragment, having V_(L), C_(L), V_(H) and C_(H)1 domains; (ii)the Fab′ fragment, which is a Fab fragment having one or more cysteineresidues at the C-terminus of the C_(H)1 domain; (iii) the Fd fragmenthaving V_(H) and C_(H)1 domains; (iv) the Fd′ fragment having V_(H) andC_(H)1 domains and one or more cysteine residues at the C-terminus ofthe CH1 domain; (v) the Fv fragment having the V_(L) and V_(H) domainsof a single arm of an antibody; (vi) a dAb fragment (Ward et al., Nature341, 544-546 (1989)) which consists of a V_(H) domain or a V_(L) domainor of V_(H), CH1, CH2, DH3, or V_(H), CH2, CH3; (vii) isolated CDRregions; (viii) F(ab′)₂ fragments, a bivalent fragment including twoFab′ fragments linked by a disulphide bridge at the hinge region; (ix)single chain antibody molecules (e.g. single chain Fv; scFv) (Bird etal., Science 242:423-426 (1988); and Huston et al., PNAS (USA)85:5879-5883 (1988)); (x) “diabodies” with two antigen binding sites,comprising a heavy chain variable domain (V_(H)) connected to a lightchain variable domain (V_(L)) in the same polypeptide chain (see, e.g.,EP 404,097; WO 93/11161; and Hollinger et al., Proc. Natl. Acad. Sci.USA, 90:6444-6448 (1993)); (xi) “linear antibodies” comprising a pair oftandem Fd segments (V_(H)-C_(H)1-V_(H)-C_(H)1) which, together withcomplementary light chain polypeptides, form a pair of antigen bindingregions (Zapata et al. Protein Eng. 8(10):1057-1062 (1995); and U.S.Pat. No. 5,641,870); and modified versions of any of the foregoing(e.g., modified by the covalent attachment of polyalkylene glycol (e.g.,polyethylene glycol, polypropylene glycol, polybutylene glycol) or othersuitable polymer).

As used herein, an “epitope” can be formed both from contiguous aminoacids, or noncontiguous amino acids juxtaposed by tertiary folding of aprotein. Epitopes formed from contiguous amino acids are typicallyretained on exposure to denaturing solvents, whereas epitopes formed bytertiary folding are typically lost on treatment with denaturingsolvents. An epitope can also be formed from non-contiguous amino acidsfound on two different proteins, which occurs only when they are boundto each other, such as, for example, when LAP binds TGF-β. Accordingly,in some embodiments of the compositions and methods described herein, ananti-LAP antibody or antigen-binding fragment thereof binds to anepitope formed from non-contiguous amino acids found when LAP is boundto TGF-β. An epitope typically includes at least 3, and, more usually,at least 5, about 9, or about 8-10 amino acids in a unique spatialconformation. An “epitope” includes the unit of structure conventionallybound by an immunoglobulin V_(H)/V_(L) pair. Epitopes define the minimumbinding site for an antibody, and thus represent the target ofspecificity of an antibody or antigen-binding fragment thereof. In thecase of a single domain antibody, an epitope represents the unit ofstructure bound by a variable domain in isolation. The terms “antigenicdeterminant” and “epitope” can also be used interchangeably herein.

With respect to a target or antigen, the term “ligand interaction site”on the target or antigen means a site, epitope, antigenic determinant,part, domain or stretch of amino acid residues on the target or antigenthat is a site for binding to a ligand, receptor or other bindingpartner, a catalytic site, a cleavage site, a site for allostericinteraction, a site involved in multimerisation (such as homomerizationor heterodimerization) of the target or antigen; or any other site,epitope, antigenic determinant, part, domain or stretch of amino acidresidues on the target or antigen that is involved in a biologicalaction or mechanism of the target or antigen. For example, in someembodiments, a ligand interaction site on LAP can be any site to whichTGF-β binds or interacts, or any site to which integrins bind orinteract, or any site to which LTBP binds or interacts. More generally,a “ligand interaction site” can be any site, epitope, antigenicdeterminant, part, domain or stretch of amino acid residues on a targetor antigen to which a binding site of a LAP binding agent describedherein can bind such that the interaction or binding between LAP and theligand (and/or any pathway, interaction, signalling, biologicalmechanism or biological effect mediated by LAP binding to a ligand isinvolved) is modulated. See, for example, Mittl et al., Protein Sci. 5:1261-1271 (1996), “The crystal structure of TGFβ3 and comparison toTGFβ2: implications for receptor binding,” the contents of which areherein incorporated by reference in their entireties.

In the context of an antibody or antigen-binding fragment thereof, theterm “specificity” or “specific for” refers to the number of differenttypes of antigens or antigenic determinants to which a particularantibody or antigen-binding fragment thereof can bind. The specificityof an antibody or antigen-binding fragment or portion thereof can bedetermined based on affinity and/or avidity. The affinity, representedby the equilibrium constant for the dissociation (K_(D)) of an antigenwith an antigen-binding protein, is a measure for the binding strengthbetween an antigenic determinant and an antigen-binding site on theantigen-binding protein: the lesser the value of the K_(D), the strongerthe binding strength between an antigenic determinant and theantigen-binding molecule. Alternatively, the affinity can also beexpressed as the affinity constant (K_(A)), which is 1/K_(D)). As willbe clear to the skilled person, affinity can be determined in a mannerknown per se, depending on the specific antigen of interest.Accordingly, an antibody or antigen-binding fragment thereof as definedherein is said to be “specific for” a first target or antigen comparedto a second target or antigen when it binds to the first antigen with anaffinity (as described above, and suitably expressed, for example as aK_(D) value) that is at least 50 times, such as at least 100 times, andpreferably at least 1000 times, and up to 10,000 times or more betterthan the affinity with which said amino acid sequence or polypeptidebinds to another target or polypeptide. Preferably, when an antibody orantigen-binding fragment thereof is “specific for” a target or antigen,compared to another target or antigen, it can bind the target orantigen, but does not bind the other target or antigen.

However, as understood by one of ordinary skill in the art, in someembodiments, where a binding site on a target is shared or partiallyshared by multiple, different ligands, an antibody or antigen bindingfragment thereof can specifically bind to a target, such as LAP, andhave the functional effect of inhibiting/preventing binding of multiple,different ligands.

Avidity is the measure of the strength of binding between anantigen-binding molecule and the pertinent antigen. Avidity is relatedto both the affinity between an antigenic determinant and its antigenbinding site on the antigen-binding molecule, and the number ofpertinent binding sites present on the antigen-binding molecule.Typically, antigen-binding proteins will bind to their cognate orspecific antigen with a dissociation constant (K_(D) of 10⁻⁵ to 10⁻¹²moles/liter or less, and preferably 10⁻⁷ to 10⁻¹² moles/liter or lessand more preferably 10⁻⁸ to 10⁻¹² moles/liter (i.e. with an associationconstant (K_(A)) of 10⁵ to 10¹² liter/moles or more, and preferably 10⁷to 10¹² liter/moles or more and more preferably 10⁸ to 10¹²liter/moles). Any K_(D) value greater than 10⁴ mol/liter (or any K_(A)value lower than 10⁴ M⁻¹) is generally considered to indicatenon-specific binding. The K_(D) for biological interactions which areconsidered meaningful (e.g., specific) are typically in the range of10⁻¹⁰ M (0.1 nM) to 10⁻⁵ M (10000 nM). The stronger an interaction is,the lower is its K_(D). Preferably, a binding site on an anti-LAPantibody or antigen-binding fragment thereof described herein will bindwith an affinity less than 500 nM, preferably less than 200 nM, morepreferably less than 10 nM, such as less than 500 pM. Specific bindingof an antigen-binding protein to an antigen or antigenic determinant canbe determined in any suitable manner known per se, including, forexample, Scatchard analysis and/or competitive binding assays, such asradioimmunoassays (RIA), enzyme immunoassays (EIA) and sandwichcompetition assays, and the different variants thereof known per se inthe art; as well as other techniques as mentioned herein.

In some embodiments of the methods described herein, the LAP bindingagent is an anti-LAP monoclonal antibody.

The term “monoclonal antibody,” as used herein, refers to an antibodyobtained from a population of substantially homogeneous antibodies,i.e., the individual antibodies comprising the population are identicalexcept for possible naturally occurring mutations that may be present inminor amounts. Monoclonal antibodies are highly specific, being directedagainst a single antigen. Furthermore, in contrast to polyclonalantibody preparations that typically include different antibodiesdirected against different determinants (epitopes), each antibody in amonoclonal preparation is directed against the same, single determinanton the antigen. It is to be understood that the term “monoclonalantibody” refers to an antibody that is derived from a single clone,including any eukaryotic, prokaryotic, or phage clone, and not themethod by which it is produced. The term “monoclonal antibody” as usedherein is not limited to antibodies produced through hybridomatechnology, and the modifier “monoclonal” is not to be construed asrequiring production of the antibody by any particular method. Forexample, the monoclonal antibodies to be used in accordance with theinvention can be made by the hybridoma method first described by Kohleret al., Nature 256:495 (1975), or later adaptations thereof, or can bemade by recombinant DNA methods (see, e.g., U.S. Pat. No. 4,816,567).The “monoclonal antibodies” can also be isolated from phage antibodylibraries using the techniques described in Clackson et al., Nature352:624-628 (1991) or Marks et al., J. Mol. Biol. 222:581-597 (1991),for example.

In some embodiments of the compositions and methods described herein,the LAP binding agent is an anti-LAP monoclonal antibody produced by anyone of hybridoma clones TW4-9E7, TW4-5A8, TW4-3E5, TW4-4E5, TW4-12B12,TW4-13B12, TW4-1G12, TW4-3G5, TW4-2F8, TW4-6H10, TW4-1G2, TW4-1E1,TW4-16F4, TW4-8F10, TW4-3H6, TW4-2C9, TW7-16B4, TW7-28G11, TW7-7H4, andTW7-20B9.

In some embodiments of the compositions and methods described herein,the LAP binding agent is an anti-LAP monoclonal having one or morebiological characteristics of an antibody produced by any one ofhybridoma clones TW4-9E7, TW4-5A8, TW4-4E5, TW4-12B12, TW4-13B12,TW4-1G12, TW4-3E5, TW4-3G5, TW4-2F8, TW4-6H10, TW4-1G2, TW4-1E1,TW4-16F4, TW4-8F10, TW4-3H6, TW4-2C9, TW7-16B4, TW7-28G11, TW7-7H4, andTW7-20B9.

As used herein, an antibody having a “biological characteristic” of adesignated antibody, such as the TW7-28G11 antibody or the TW7-16B4, isone that possesses one or more of the biological characteristics of thatantibody which distinguish it from other antibodies that bind to thesame antigen. For example, a biological characteristics of the TW7-28G11monoclonal antibody includes having an ED₅₀ value (i.e., the dosetherapeutically effective in 50% of the population) at or around theED₅₀ value of the TW7-28G11 antibody for the given population; having anEC₅₀ value (i.e., the dose that achieves a half-maximal inhibition of agiven parameter or phenotype) at or around the EC₅₀ value of theTW7-28G11 antibody for a given parameter or phenotype. The effects ofany particular dosage can be monitored by a suitable bioassay. Forexample, in some embodiments of these aspects, the given parameter orphenotype to be inhibited by the anti-LAP antibody that specificallybinds to LAP and has one or more biological characteristics of theTW7-28G11 antibody can include, but is not limited to, the ability tospecifically bind both human and mouse LAP and/or prevent or inhibitrelease of TGF-β from the small latent complex, and/or selectivelydeplete regulatory T cell populations, such as CD4+ regulatory T cellsexpressing LAP and/or CD103+CD8 T cells.

In some embodiments of the aspects described herein, anti-LAP antibodiesfor use in the compositions and methods described herein includemonoclonal antibodies that bind to the same epitope or epitopes of LAPas the monoclonal antibody produced by any one of hybridoma clonesTW4-9E7, TW4-5A8, TW4-3E5, TW4-4E5, TW4-12B12, TW4-13B12, TW4-1G12,TW4-3G5, TW4-2F8, TW4-6H10, TW4-1G2, TW4-1E1, TW4-16F4, TW4-8F10,TW4-3H6, TW4-2C9, TW7-16B4, TW7-28G11, TW7-7H4, and TW7-20B9.

In some aspects, the anti-LAP monoclonal antibody is the monoclonalanti-LAP antibody TW7-28G11 produced or expressed by the hybridomaTW7-28G11 described herein, and referred to as the “TW7-28G11 antibody”or “TW7-28G11 anti-LAP antibody” and derivatives or antigen-bindingfragments thereof, including, for example, a “TW7-28G11 variable heavychain,” or a “TW7-28G11 variable light chain.”

As described herein, the TW7-28G11 hybridoma produces a monoclonalantibody termed herein as the “TW7-28G11 anti-LAP antibody” or“TW7-28G11 antibody,” or the “variant TW7-28G11 anti-LAP monoclonalantibody” that is highly specific for LAP and can potently inhibit LAPbiological activity and provide highly therapeutic effects in thetreatment of cancer. As shown herein, the TW7-28G11 anti-LAP antibodybinds both human and mouse LAP and prevents or inhibits release of TGF-βfrom the small latent complex and selectively depletes regulatory T cellpopulations, such as CD4+ regulatory T cells expressing LAP and/orCD103+CD8 T cells when administered in vivo. The biologicalcharacteristics of the TW7-28G11 anti-LAP antibody, and anyantigen-binding fragments derived or generated therefrom, render itparticularly useful for the compositions and methods described herein,including therapeutic and diagnostic applications. Accordingly, sequenceanalysis of the TW7-28G11 antibody was performed, as described herein,to identify the heavy and light chain variable domain sequences, andcomplementarity determining region (CDR) sequences, of the TW7-28G11antibody for use in the compositions and methods described herein.

Throughout the present specification and claims, the numbering of theresidues in an immunoglobulin heavy chain is that of the EU index as inKabat et al., Sequences of Proteins of Immunological Interest, 5th Ed.Public Health Service, National Institutes of Health, Bethesda, Md.(1991), which is also available on the world wide web, and is expresslyincorporated herein in its entirety by reference. The “EU index as inKabat” refers to the residue numbering of the human IgG1 EU antibody. Asused herein, “Kabat sequence numbering” or “Kabat labeling” refer tonumbering of the sequence encoding a variable region according to the EUindex as in Kabat. For the heavy chain variable region, thehypervariable region ranges from amino acid positions 31 to 35 for CDR1,amino acid positions 50 to 65 for CDR2, and amino acid positions 95 to102 for CDR3, according to the Kabat numbering. For the light chainvariable region, the hypervariable region ranges from amino acidpositions 24 to 34 for CDR1, amino acid positions 50 to 56 for CDR2, andamino acid positions 89 to 97 for CDR3, according to the Kabatnumbering. In some embodiments, IMGT (INTERNATIONAL IMMUNOGENETICSINFORMATION SYSTEM) numbering of variable regions can also be used,which is the numbering of the residues in an immunoglobulin variableheavy or light chain according to the methods of the IIMGT, as describedin Lefranc, M.-P., “The IMGT unique numbering for immunoglobulins, Tcell Receptors and Ig-like domains”, The Immunologist, 7, 132-136(1999), and is expressly incorporated herein in its entirety byreference. As used herein, “IMGT sequence numbering” refers to numberingof the sequence encoding a variable region according to the IMGT.

The nucleotide sequence encoding a V_(H) or variable domain of the heavychain of the TW7-28G11 antibody, as obtained by analysis of sequencesobtained from the TW7-28G11 hybridoma, is:

(SEQ ID NO: 7) ATGAAGTTGTGGCTGAACTGGATTTTCCTTGTAACACTTTTAAATGATATCCAGTGTGAGGTGAAGCTGGTGGAGTCTGGAGGAGGCTTGGTACAGCCTGGGGGTTCTCTGAGTCTCTCCTGTGCAGCTTCTGGATTCACCTTCACTGATTACTACATGAGCTGGGTCCGCCAGCCTCCAGGGAAGGCACTTGAGTGGTTGGGTTTTATTAGAAACAAACCTAATGGTTACACAACAGAGTACAGTGCATCTGTGAAGGGTCGGTTCACCATCTCCAGAGATAATTCCCAAAGCATCCTCTATCTTCAAATGAATGTCCTGAGAGCTGAGGACAGTGCCACTTATTACTGTGCAAGATATACGGGGGGGGGTTACTTTGACTACTGGGGCCAAGGCACCACTCTCACAGTCTCCTCA.

The amino acid sequence of the V_(H) domain of the TW7-28G11 antibodycorresponding to SEQ ID NO: 7 is:

(SEQ ID NO: 8) MKLWLNWIFLVTLLNDIQCEVKLVESGGGLVQPGGSLSLSCAASGFTFTDYYMSWVRQPPGKALEWLGFIRNKPNGYTTEYSASVKGRFTISRDNSQSILYLQMNVLRAEDSATYYCARYTGGGYFDYWGQGTTLTVSS.

The amino acid sequence of the complementarity determining region 1 orCDR1 of the V_(H) domain of SEQ ID NO: 8 of the TW7-28G11 antibodyaccording to the Kabat sequence numbering is: DYYMS (SEQ ID NO: 9). Theamino acid sequence of the CDR2 of the V_(H) domain of SEQ ID NO: 8 ofthe TW7-28G11 antibody according to the Kabat sequence numbering is:FIRNKPNGYTTEYSASVKG (SEQ ID NO: 10). The amino acid sequence of the CDR3of the V_(H) domain of SEQ ID NO: 8 of the TW7-28G11 antibody accordingto the Kabat sequence numbering is:

(SEQ ID NO: 11) YTGGGYFDY.

The nucleotide sequence encoding a V_(L) or variable domain of the lightchain of the TW7-28G11 antibody, as obtained by analysis of sequencesobtained from the TW7-28G11 hybridoma, is:

(SEQ ID NO: 12) ATGATGTCCTCTGCTCAGTTCCTTGGTCTCCTGTTGCTCTGTTTTCAAGGTACCAGATGTGATATCCAGATGACACAGACTACATCCTCCCTGTCTGCCTCTCTGGGAGACAGACTCACCATCAGTTGCAGGGCAAGTCAGGACATTAGCAATTATTTAAACTGGTATCAGCAGAAACCAGATGGAACTGTTAAACTCCTGATCTACTACACATCAAGATTACACTCAGGAGTCCCATCAAGGTTCAGTGGCAGTGGGTCTGGAACAGATTATTCTCTCACCATTAGCAACCTGGAGCAAGCAGATATTGCCACTTACTTTTGCCAACAGGGTGATACACTTCCGTGGACGTTCGGTGGAGGCACCAAGCTGGAAA TCAAA.

The amino acid sequence of the V_(L) domain of the TW7-28G11 antibodycorresponding to SEQ ID NO: 12 is:

(SEQ ID NO: 13) MMSSAQFLGLLLLCFQGTRCDIQMTQTTSSLSASLGDRLTISCRASQDISNYLNWYQQKPDGTVKLLIYYTSRLHSGVPSRFSGSGSGTDYSLTISNLEQADIATYFCQQGDTLPWTFGGGTKLEIK.

The amino acid sequence of the complementarity determining region 1 orCDR1 of the V_(L) domain of SEQ ID NO: 13 of the TW7-28G11 antibodyaccording to the Kabat sequence numbering is: RASQDISNYLN (SEQ ID NO:14). The amino acid sequence of the CDR2 of the V_(L) domain of SEQ IDNO: 13 of the TW7-28G11 antibody according to the Kabat sequencenumbering is: YTSRLHS (SEQ ID NO: 15). The amino acid sequence of theCDR3 of the V_(L) domain of SEQ ID NO: 13 of the TW7-28G11 antibodyaccording to the Kabat sequence numbering is: QQGDTLPWT (SEQ ID NO: 16).

The amino acid sequence of the framework 1 or FR1 region of the V_(H)domain of SEQ ID NO: 8 of the TW7-28G11 antibody according to the Kabatsequence numbering is: EVKLVESGGGLVQPGGSLSLSCAASGFTFT (SEQ ID NO: 17).The amino acid sequence of the framework 2 or FR2 region of the V_(H)domain of SEQ ID NO: 8 of the TW7-28G11 antibody according to the Kabatsequence numbering is: WVRQPPGKALEWLG (SEQ ID NO: 18). The amino acidsequence of the framework 3 or FR3 region of the V_(H) domain of SEQ IDNO: 8 of the TW7-28G11 antibody according to the Kabat sequencenumbering is: RFTISRDNSQSILYLQMNVLRAEDSATYYCAR (SEQ ID NO: 19). Theamino acid sequence of the framework 4 or FR4 region of the V_(H) domainof SEQ ID NO: 8 of the TW7-28G11 antibody according to the Kabatsequence numbering is: WGQGTTLTVSS (SEQ ID NO: 20).

The amino acid sequence of the framework 1 or FR1 region of the V_(L)domain of SEQ ID NO: 13 of the TW7-28G11 antibody according to the Kabatsequence numbering is: DIQMTQTTSSLSASLGDRLTISC (SEQ ID NO: 21). Theamino acid sequence of the framework 2 or FR2 region of the V_(L) domainof SEQ ID NO: 13 of the TW7-28G11 antibody according to the Kabatsequence numbering is: WYQQKPDGTVKLLIY (SEQ ID NO: 22). The amino acidsequence of the framework 3 or FR3 region of the V_(L) domain of SEQ IDNO: 13 of the TW7-28G11 antibody according to the Kabat sequencenumbering is: GVPSRFSGSGSGTDYSLTISNLEQADIATYFC (SEQ ID NO: 23). Theamino acid sequence of the framework 2 or FR2 region of the V_(L) domainof SEQ ID NO: 13 of the TW7-28G11 antibody according to the Kabatsequence numbering is: FGGGTKLEIK (SEQ ID NO: 24).

Accordingly, in some embodiments of the aspects provided herein, theheavy and/or light chain variable domain(s) sequence(s) of the TW7-28G11antibody, i.e., SEQ ID NO: 8, and/or SEQ ID NO: 13, and their respectiveCDR sequences SEQ ID NOs: 9-11 and SEQ ID NOs: 14-16 can be used togenerate, for example, CDR-grafted, chimeric, humanized, or compositehuman antibodies or antigen-binding fragments, as described elsewhereherein. As understood by one of ordinary skill in the art, any variant,CDR-grafted, chimeric, humanized, or composite antibodies orantigen-binding fragments derived from the TW7-28G11 antibody or any oneof the antibodies produced by hybrodimas TW4-9E7, TW4-5A8, TW4-3E5,TW4-4E5, TW4-12B12, TW4-13B12, TW4-1G12, TW4-3G5, TW4-2F8, TW4-6H10,TW4-1G2, TW4-1E1, TW4-16F4, TW4-8F10, TW4-3H6, TW4-2C9, TW7-16B4,TW7-28G11, TW7-7H4, and TW7-20B9 useful in the compositions and methodsdescribed herein will maintain the ability to immunospecifically bindLAP, such that the variant, CDR-grafted, chimeric, humanized, orcomposite antibody or antigen-binding fragment thereof has at least 50%,at least 60%, at least 70%, at least 80%, at least 90%, at least 95% ormore binding to LAP relative to the original antibody from which it isderived.

In some embodiments of the aspects described herein, an anti-LAPantibody or an antigen-binding fragment thereof described herein, whichspecifically binds to LAP (e.g., human LAP), comprises a light chainvariable region (V_(L)) comprising V_(L) CDR1 of SEQ ID NO: 14, V_(L)CDR2 of SEQ ID NO: 15, and V_(L) CDR3 of SEQ ID NO: 14, or the V_(L)CDR1, V_(L) CDR2, and V_(L) CDR3 of any one of the antibodies producedby hybrodimas TW4-9E7, TW4-5A8, TW4-3E5, TW4-4E5, TW4-12B12, TW4-13B12,TW4-1G12, TW4-3G5, TW4-2F8, TW4-6H10, TW4-1G2, TW4-1E1, TW4-16F4,TW4-8F10, TW4-3H6, TW4-2C9, TW7-16B4, TW7-28G11, TW7-7H4, and TW7-20B9.In some embodiments, the anti-LAP antibody or antigen-binding fragmentthereof comprises V_(L) framework regions of the TW7-28G11 antibody. Insome embodiments of the aspects described herein, the anti-LAP antibodyor antigen-binding fragment thereof comprises a light chain variableregion sequence comprising one, two, three or four of the frameworkregions of the light chain variable region sequence of SEQ ID NO: 13. Insome embodiments of the aspects described herein, the anti-LAP antibodyor antigen-binding fragment thereof comprises one, two, three or four ofthe framework regions of a light chain variable region sequence which isat least 75%, 80%, 85%, 90%, 95%, or 100% identical to one, two, threeor four of the framework regions of the light chain variable regionsequence of SEQ ID NO: 13. In some embodiments of the aspects describedherein, the light chain variable framework region that is derived fromsaid amino acid sequence consists of said amino acid sequence but forthe presence of up to 10 amino acid substitutions, deletions, and/orinsertions, preferably up to 10 amino acid substitutions. In someembodiments of the aspects described herein, the light chain variableframework region that is derived from said amino acid sequence consistsof said amino acid sequence with 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 aminoacid residues being substituted for an amino acid found in an analogousposition in a corresponding non-human, primate, or human light chainvariable framework region.

In some embodiments of the aspects described herein, an anti-LAPantibody or antigen-binding fragment thereof described herein thatspecifically binds to LAP comprises the V_(L) CDR1, V_(L) CDR2, andV_(L) CDR3 of SEQ ID NOS: 14, 15, and 16, respectively. In someembodiments of the aspects described herein, the antibody orantigen-binding fragment further comprises one, two, three or all fourV_(L) framework regions derived from the V_(L) of a human or primateantibody. The primate or human light chain framework region of theantibody selected for use with the light chain CDR sequences describedherein, can have, for example, at least 70% identity with a light chainframework region of the non-human parent antibody, for example, SEQ IDNOs: 21-24. The primate or human antibody selected can have the same orsubstantially the same number of amino acids in its light chaincomplementarity determining regions to that of the light chaincomplementarity determining regions of the TW7-28G11 antibody, i.e., SEQID NOs: 14-16. In some embodiments of the aspects described herein, theprimate or human light chain framework region amino acid residues arefrom a natural primate or human antibody light chain framework regionhaving at least 75% identity, at least 80% identity, at least 85%identity (or more) with the light chain framework regions of theTW7-28G11 antibody, namely SEQ ID NOs: 20-24. In some embodiments, theanti-LAP antibody or antigen-binding fragment further comprises one,two, three or all four V_(L) framework regions derived from a humanlight chain variable kappa subfamily. In some embodiments, the anti-LAPantibody or antigen-binding fragment further comprises one, two, threeor all four VL framework regions derived from a human light chainvariable lambda subfamily.

In some embodiments of the aspects described herein, an anti-LAPantibody or fragment thereof described herein that specifically binds toLAP comprises the heavy chain variable region (V_(H)) comprising V_(H)CDR1, V_(H) CDR2, and V_(H) CDR3 of SEQ ID NOS: 9, 10, and 11,respectively, or the V_(H) CDR1, V_(H) CDR2, and V_(H) CDR3 of any oneof the antibodies produced by hybrodimas TW4-9E7, TW4-5A8, TW4-3E5,TW4-4E5, TW4-12B12, TW4-13B12, TW4-1G12, TW4-3G5, TW4-2F8, TW4-6H10,TW4-1G2, TW4-1E1, TW4-16F4, TW4-8F10, TW4-3H6, TW4-2C9, TW7-16B4,TW7-28G11, TW7-7H4, and TW7-20B9. In some embodiments of the aspectsdescribed herein, the anti-LAP antibody or antigen-binding fragmentthereof comprises one, two, three or all four of the framework regionsof the heavy chain variable region sequence of SEQ ID NO: 8. In someembodiments of the aspects described herein, the anti-LAP antibody orantigen-binding fragment thereof comprises one, two, three, or four ofthe framework regions of a heavy chain variable region sequence which isat least 75%, 80%, 85%, 90%, 95% or 100% identical to one, two, three orfour of the framework regions of the heavy chain variable regionsequence of SEQ ID NO: 8. In some embodiments of the aspects describedherein, the heavy chain variable framework region that is derived fromsaid amino acid sequence consists of said amino acid sequence but forthe presence of up to 10 amino acid substitutions, deletions, and/orinsertions, preferably up to 10 amino acid substitutions. In someembodiments of the aspects described herein, the heavy chain variableframework region that is derived from said amino acid sequence consistsof said amino acid sequence with 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 aminoacid residues being substituted for an amino acid found in an analogousposition in a corresponding non-human, primate, or human heavy chainvariable framework region.

In some embodiments of the aspects described herein, an anti-LAPantibody or fragment thereof described herein that specifically binds toLAP comprises the V_(H) CDR1, V_(H) CDR2, and V_(H) CDR3 of SEQ ID NOS:9, 10, and 11, respectively. In some embodiments of the aspectsdescribed herein, the anti-LAP antibody or antigen-binding fragmentfurther comprises one, two, three or all four V_(H) framework regionsderived from the V_(H) of a human or primate antibody. The primate orhuman heavy chain framework region of the antibody selected for use withthe heavy chain CDR sequences described herein, can have, for example,at least 70% identity with a heavy chain framework region of thenon-human parent antibody, for example, SEQ ID NOs: 17-20. Preferably,the primate or human antibody selected can have the same orsubstantially the same number of amino acids in its heavy chaincomplementarity determining regions to that of the light chaincomplementarity determining regions of the TW7-28G11 antibody, i.e., SEQID NOs: 9-11. In some embodiments of the aspects described herein, theprimate or human heavy chain framework region amino acid residues arefrom a natural primate or human antibody heavy chain framework regionhaving at least 75% identity, at least 80% identity, at least 85%identity (or more) with the heavy chain framework regions of theTW7-28G11 antibody, namely SEQ ID NOs: 17-20. In specific embodiments,the antibody or antigen-binding fragment further comprises one, two,three or all four V_(H) framework regions derived from a human heavychain variable subfamily (e.g., one of subfamilies 1 to 7).

In some embodiments of the aspects described herein, an anti-LAPantibody or fragment thereof described herein that specifically binds toLAP comprises (i) a heavy chain variable region (V_(H)) comprising V_(H)CDR1, V_(H) CDR2, and V_(H) CDR3 of SEQ ID NOS: 9, 10, and 11,respectively and (ii) a light chain variable region (V_(L)) comprisingV_(L) CDR1, V_(L) CDR2, and V_(L) CDR3 of SEQ ID NOS: 14, 15, and 16,respectively. In some embodiments of the aspects described herein, theanti-LAP antibody or antigen-binding fragment thereof described hereincomprises one, two, three or four framework regions of a heavy chainvariable region sequence which is at least 75%, 80%, 85%, 90%, 95% or100% identical to one, two, three or four of the framework regions of aheavy chain variable region sequence of SEQ ID NO: 8. In someembodiments of the aspects described herein, the heavy chain variableframework region that is derived from said amino acid sequence consistsof said amino acid sequence but for the presence of up to 10 amino acidsubstitutions, deletions, and/or insertions, preferably up to 10 aminoacid substitutions. In some embodiments of the aspects described herein,the heavy chain variable framework region that is derived from saidamino acid sequence consists of said amino acid sequence with 1, 2, 3,4, 5, 6, 7, 8, 9 or 10 amino acid residues being substituted for anamino acid found in an analogous position in a corresponding non-human,primate, or human heavy chain variable framework region. In someembodiments of the aspects described herein, the anti-LAP antibody orantigen-binding fragment thereof comprises a light chain variable regionsequence comprising one, two, three or four of the framework regions ofthe light chain variable region sequence of SEQ ID NO: 13. In someembodiments of the aspects described herein, the anti-LAP antibody orantigen-binding fragment thereof comprises one, two, three or fourframework regions of a light chain variable region sequence which is atleast 75%, 80%, 85%, 90%, 95%, or 100% identical to one, two, three orfour of the framework regions of a light chain variable region of SEQ IDNO: 13. In some embodiments of the aspects described herein, the lightchain variable framework region that is derived from said amino acidsequence consists of said amino acid sequence but for the presence of upto 10 amino acid substitutions, deletions, and/or insertions, preferablyup to 10 amino acid substitutions. In some embodiments of the aspectsdescribed herein, the light chain variable framework region that isderived from said amino acid sequence consists of said amino acidsequence with 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 amino acid residues beingsubstituted for an amino acid found in an analogous position in acorresponding non-human, primate, or human light chain variableframework region. The primate or human light chain framework region ofthe antibody selected for use with the light chain CDR sequencesdescribed herein, can have, for example, at least 70% identity with alight chain framework region of the non-human parent antibody, forexample, SEQ ID NOs: 21-24. The primate or human antibody selected canhave the same or substantially the same number of amino acids in itslight chain complementarity determining regions to that of the lightchain complementarity determining regions of the TW7-28G11 antibody,i.e., SEQ ID NOs: 14-16. In some embodiments of the aspects describedherein, the primate or human light chain framework region amino acidresidues are from a natural primate or human antibody light chainframework region having at least 75% identity, at least 80% identity, atleast 85% identity (or more) with the light chain framework regions ofthe TW7-28G11 antibody, namely SEQ ID NOs: 20-24. The primate or humanheavy chain framework region of the antibody selected for use with theheavy chain CDR sequences described herein, can have, for example, atleast 70% identity with a heavy chain framework region of the non-humanparent antibody, for example, SEQ ID NOs: 17-20. Preferably, the primateor human antibody selected can have the same or substantially the samenumber of amino acids in its heavy chain complementarity determiningregions to that of the light chain complementarity determining regionsof the TW7-28G11 antibody, i.e., SEQ ID NOs: 9-11. In some embodimentsof the aspects described herein, the primate or human heavy chainframework region amino acid residues are from a natural primate or humanantibody heavy chain framework region having at least 75% identity, atleast 80% identity, at least 85% identity (or more) with the heavy chainframework regions of the TW7-28G11 antibody, namely SEQ ID NOs: 17-20.In specific embodiments, the antibody or antigen-binding fragmentfurther comprises one, two, three or all four VH framework regionsderived from a human heavy chain variable subfamily (e.g., one ofsubfamilies 1 to 7).

In some embodiments of the aspects described herein, an anti-LAPantibody or fragment thereof that specifically binds to LAP comprisesthe V_(L) CDR1, V_(L) CDR2, V_(L) CDR3, V_(H) CDR1, V_(H) CDR2, andV_(H) CDR3 of SEQ ID NOS: 14, 15, 16, 9, 10, and 11, respectively. Incertain embodiments, the anti-LAP antibody or antigen-binding fragmentfurther comprises one, two, three or all four V_(L) framework regionsderived from the V_(L) of a human or primate antibody and one, two,three or all four V_(H) framework regions derived from the V_(H) of ahuman or primate antibody. The primate or human light chain frameworkregion of the antibody selected for use with the light chain CDRsequences described herein, can have, for example, at least 70% identitywith a light chain framework region of the non-human parent antibody,for example, SEQ ID NOs: 21-24. The primate or human antibody selectedcan have the same or substantially the same number of amino acids in itslight chain complementarity determining regions to that of the lightchain complementarity determining regions of the TW7-28G11 antibody,i.e., SEQ ID NOs: 14-16. In some embodiments of the aspects describedherein, the primate or human light chain framework region amino acidresidues are from a natural primate or human antibody light chainframework region having at least 75% identity, at least 80% identity, atleast 85% identity (or more) with the light chain framework regions ofthe TW7-28G11 antibody, namely SEQ ID NOs: 20-24. The primate or humanheavy chain framework region of the antibody selected for use with theheavy chain CDR sequences described herein, can have, for example, atleast 70% identity with a heavy chain framework region of the non-humanparent antibody, for example, SEQ ID NOs: 17-20. Preferably, the primateor human antibody selected can have the same or substantially the samenumber of amino acids in its heavy chain complementarity determiningregions to that of the light chain complementarity determining regionsof the TW7-28G11 antibody, i.e., SEQ ID NOs: 9-11. In some embodimentsof the aspects described herein, the primate or human heavy chainframework region amino acid residues are from a natural primate or humanantibody heavy chain framework region having at least 75% identity, atleast 80% identity, at least 85% identity (or more) with the heavy chainframework regions of the TW7-28G11 antibody, namely SEQ ID NOs: 17-20.In specific embodiments, the anti-LAP antibody or antigen-bindingfragment further comprises one, two, three or all four V_(H) frameworkregions derived from a human heavy chain variable subfamily (e.g., oneof subfamilies 1 to 7).

In some embodiments of the aspects described herein, an antibody orfragment thereof that specifically binds to LAP comprises the amino acidsequence of a V_(L) domain of SEQ ID NO: 13. In some embodiments of theaspects described herein, an antibody or fragment thereof thatspecifically binds to LAP comprises a V_(L) domain consisting of orconsisting essentially of the amino acid sequence of SEQ ID NO: 13.

In some embodiments of the aspects described herein, an anti-LAPantibody or fragment thereof that specifically binds to LAP comprisesthe amino acid sequence of a V_(H) domain comprising the amino acidsequence of a V_(H) domain of SEQ ID NO: 8. In some embodiments of theaspects described herein, an anti-LAP antibody or fragment thereof thatspecifically binds to LAP comprises a V_(H) domain consisting of orconsisting essentially of the amino acid sequence of SEQ ID NO: 8.

In some embodiments of the aspects described herein, an anti-LAPantibody or fragment thereof that specifically binds to LAP comprises aV_(H) domain comprising the amino acid sequence of a V_(H) domain of SEQID NO: 8 and a V_(L) domain comprising the amino acid sequence of SEQ IDNO: 13. some embodiments of the aspects described herein, an anti-LAPantibody or fragment thereof that specifically binds to LAP comprises aV_(H) domain consisting of or consisting essentially of the amino acidsequence of SEQ ID NO: 8 and a V_(L) domain consisting of or consistingessentially of the amino acid sequence of SEQ ID NO: 13.

An antibody or antigen-binding fragment described herein can bedescribed by its V_(L) domain alone, or its V_(H) domain alone, or byits 3 V_(L) CDRs alone, or its 3 V_(H) CDRs alone. See, for example,Rader C et al., (1998) PNAS 95: 8910-8915, which is incorporated hereinby reference in its entirety, describing the humanization of the mouseanti-αvβ3 antibody by identifying a complementing light chain or heavychain, respectively, from a human light chain or heavy chain library,resulting in humanized antibody variants having affinities as high orhigher than the affinity of the original antibody. See also, Clackson Tet al., (1991) Nature 352: 624-628, which is incorporated herein byreference in its entirety, describing methods of producing antibodiesthat bind a specific antigen by using a specific V_(L) domain (or V_(H)domain) and screening a library for the complementary variable domains.

In some embodiments of the aspects described herein, the position of oneor more CDRs along the V_(H) (e.g., CDR1, CDR2, or CDR3) and/or VL(e.g., CDR1, CDR2, or CDR3) region of an antibody described herein canvary by one, two, three, four, five, or six amino acid positions so longas immunospecific binding to LAP (e.g., human LAP) is maintained (e.g.,substantially maintained, for example, at least 50%, at least 60%, atleast 70%, at least 80%, at least 90%, at least 95% of the binding ofthe original antibody from which it is derived). For example, in someembodiments, the position defining a CDR of any antibody describedherein (e.g., any one of the antibodies produced by hybrodimas TW4-9E7,TW4-5A8, TW4-3E5, TW4-4E5, TW4-12B12, TW4-13B12, TW4-1G12, TW4-3G5,TW4-2F8, TW4-6H10, TW4-1G2, TW4-1E1, TW4-16F4, TW4-8F10, TW4-3H6,TW4-2C9, TW7-16B4, TW7-28G11, TW7-7H4, and TW7-20B9) can vary byshifting the N-terminal and/or C-terminal boundary of the CDR by one,two, three, four, five, or six amino acids, relative to the CDR positionof any one of the antibodies described herein, so long as immunospecificbinding to LAP (e.g., human LAP) is maintained (e.g., substantiallymaintained, for example, at least 50%, at least 60%, at least 70%, atleast 80%, at least 90%, at least 95% of the binding of the originalantibody from which it is derived). In another embodiment, the length ofone or more CDRs along the V_(H) (e.g., CDR1, CDR2, or CDR3) and/orV_(L) (e.g., CDR1, CDR2, or CDR3) region of an antibody described hereincan vary (e.g., be shorter or longer) by one, two, three, four, five, ormore amino acids, so long as immunospecific binding to LAP (e.g., humanLAP) is maintained (e.g., substantially maintained, for example, atleast 50%, at least 60%, at least 70%, at least 80%, at least 90%, atleast 95% of the binding of the original antibody from which it isderived).

Accordingly, in some embodiments of the aspects described herein, aV_(L) CDR1, VL CDR2, V_(L) CDR3, V_(H) CDR1, V_(H) CDR2, and/or V_(H)CDR3 described herein may be one, two, three, four, five or more aminoacids shorter than one or more of the CDRs described herein (e.g., SEQID NO: 14-16, and 9-11) so long as immunospecific binding to LAP (e.g.,human LAP) is maintained (e.g., substantially maintained, for example,at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, atleast 95% relative to the binding of the original antibody from which itis derived). In some embodiments of the aspects described herein, aV_(L) CDR1, V_(L) CDR2, V_(L) CDR3, V_(H) CDR1, V_(H) CDR2, and/or V_(H)CDR3 described herein may be one, two, three, four, five or more aminoacids longer than one or more of the CDRs described herein (e.g., SEQ IDNO: 14-16, and 9-11) so long as immunospecific binding to LAP (e.g.,human LAP) is maintained (e.g., substantially maintained, for example,at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, atleast 95% relative to the binding of the original antibody from which itis derived). In some embodiments of the aspects described herein, theamino terminus of a V_(L) CDR1, V_(L) CDR2, V_(L) CDR3, V_(H) CDR1,V_(H) CDR2, and/or V_(H) CDR3 described herein can be extended by one,two, three, four, five or more amino acids compared to one or more ofthe CDRs described herein (e.g., SEQ ID NO: 14-16, and 9-11) so long asimmunospecific binding to LAP (e.g., human LAP) is maintained (e.g.,substantially maintained, for example, at least 50%, at least 60%, atleast 70%, at least 80%, at least 90%, at least 95% relative to thebinding of the original antibody from which it is derived). In someembodiments of the aspects described herein, the carboxy terminus of aV_(L) CDR1, V_(L) CDR2, V_(L) CDR3, V_(H) CDR1, V_(H) CDR2, and/or V_(H)CDR3 described herein can be extended by one, two, three, four, five ormore amino acids compared to one or more of the CDRs described herein(e.g., SEQ ID NO: 14-16, and 9-11) so long as immunospecific binding toLAP (e.g., human LAP) is maintained (e.g., substantially maintained, forexample, at least 50%, at least 60%, at least 70%, at least 80%, atleast 90%, at least 95 relative to the binding of the original antibodyfrom which it is derived). In some embodiments of the aspects describedherein, the amino terminus of a V_(L) CDR1, VL CDR2, V_(L) CDR3, V_(H)CDR1, V_(H) CDR2, and/or V_(H) CDR3 described herein can be shortened byone, two, three, four, five or more amino acids compared to one or moreof the CDRs described herein (e.g., SEQ ID NO: 14-16, and 9-11) so longas immunospecific binding to LAP (e.g., human LAP) is maintained (e.g.,substantially maintained, for example, at least 50%, at least 60%, atleast 70%, at least 80%, at least 90%, at least 95 relative to thebinding of the original antibody from which it is derived). In someembodiments of the aspects described herein, the carboxy terminus of aV_(L) CDR1, V_(L) CDR2, V_(L) CDR3, V_(H) CDR1, V_(H) CDR2, and/or V_(H)CDR3 described herein can be shortened by one, two, three, four, five ormore amino acids compared to one or more of the CDRs described herein(e.g., SEQ ID NO: 14-16, and 9-11) so long as immunospecific binding toLAP (e.g., human LAP) is maintained (e.g., substantially maintained, forexample, at least 50%, at least 60%, at least 70%, at least 80%, atleast 90%, at least 95 relative to the binding of the original antibodyfrom which it is derived). Any method known in the art can be used toascertain whether immunospecific binding to LAP (e.g., human LAP) ismaintained, for example, the binding assays and conditions described inthe “Examples” section provided herein.

With respect to the heavy chain, in some embodiments of the aspectsdescribed herein, the heavy chain of an antibody described herein can bean alpha (α), delta (Δ), epsilon (ε), gamma (γ) or mu (μ) heavy chain.In some embodiments of the aspects described herein, the heavy chain ofan antibody described can comprise a human alpha (α), delta (Δ), epsilon(ε), gamma (γ) or mu (μ) heavy chain. In a particular embodiment, anantibody described herein comprises a heavy chain wherein the amino acidsequence of the V_(H) domain comprises SEQ ID NO: 8, and wherein theconstant region of the heavy chain comprises the amino acid sequence ofa human gamma (γ) heavy chain constant region, such as any known in theart. Non-limiting examples of human constant region sequences have beendescribed in the art, e.g., see U.S. Pat. No. 5,693,780 and Kabat E A etal., (1991) supra.

In some embodiments of the aspects described herein, an anti-LAPantibody comprises a V_(L) domain and a V_(H) domain comprising SEQ IDNO: 13 and/or SEQ ID NO: 8, and wherein the constant regions comprisethe amino acid sequences of the constant regions of an IgG, IgE, IgM,IgD, IgA or IgY immunoglobulin molecule, or a human IgG, IgE, IgM, IgD,IgA or IgY immunoglobulin molecule. In some embodiments of the aspectsdescribed herein, an anti-LAP antibody comprises a V_(L) domain and aV_(H) domain comprising SEQ ID NO: 13 and/or SEQ ID NO: 8, and whereinthe constant regions comprise the amino acid sequences of the constantregions of an IgG, IgE, IgM, IgD, IgA or IgY immunoglobulin molecule,any class (e.g., IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2), or any subclass(e.g., IgG2a and IgG2b) of immunoglobulin molecule. Non-limitingexamples of human constant regions are described in the art, e.g., seeKabat E A et al., (1991) supra.

In some embodiments of the aspects described herein, one, two or moremutations (e.g., amino acid substitutions) are introduced into the Fcregion of an anti-LAP antibody described herein or a fragment thereof(e.g., CH2 domain (residues 231-340 of human IgG1) and/or CH3 domain(residues 341-447 of human IgG1) and/or the hinge region, with numberingaccording to the Kabat numbering system (e.g., the EU index in Kabat))to alter one or more functional properties of the antibody, such asserum half-life, complement fixation, Fc receptor binding and/orantigen-dependent cellular cytotoxicity.

In some embodiments of the aspects described herein, one, two or moremutations (e.g., amino acid substitutions) are introduced into the hingeregion of the Fc region (CH1 domain) such that the number of cysteineresidues in the hinge region are altered (e.g., increased or decreased)as described in, e.g., U.S. Pat. No. 5,677,425. The number of cysteineresidues in the hinge region of the CH1 domain can be altered to, e.g.,facilitate assembly of the light and heavy chains, or to alter (e.g.,increase or decrease) the stability of the antibody.

In some embodiments of the aspects described herein, one, two or moremutations (e.g., amino acid substitutions) are introduced into the Fcregion of an anti-LAP antibody described herein or a fragment thereof(e.g., CH2 domain (residues 231-340 of human IgG1) and/or CH3 domain(residues 341-447 of human IgG1) and/or the hinge region, with numberingaccording to the Kabat numbering system (e.g., the EU index in Kabat))to increase or decrease the affinity of the antibody for an Fc receptor(e.g., an activated Fc receptor) on the surface of an effector cell.Mutations in the Fc region of an antibody or fragment thereof thatdecrease or increase the affinity of an antibody for an Fc receptor andtechniques for introducing such mutations into the Fc receptor orfragment thereof are known to one of skill in the art. Examples ofmutations in the Fc receptor of an antibody that can be made to alterthe affinity of the antibody for an Fc receptor are described in, e.g.,Smith Petal., (2012) PNAS 109: 6181-6186, U.S. Pat. No. 6,737,056, andInternational Publication Nos. WO 02/060919; WO 98/23289; and WO97/34631, which are incorporated herein by reference.

In some embodiments of the aspects described herein, one, two or moreamino acid mutations (i.e., substitutions, insertions or deletions) areintroduced into an IgG constant domain, or FcRn-binding fragment thereof(preferably an Fc or hinge-Fc domain fragment) to alter (e.g., decreaseor increase) half-life of the antibody in vivo. See, e.g., InternationalPublication Nos. WO 02/060919; WO 98/23289; and WO 97/34631; and U.S.Pat. Nos. 5,869,046, 6,121,022, 6,277,375 and 6,165,745 for examples ofmutations that will alter (e.g., decrease or increase) the half-life ofan antibody in vivo.

In some embodiments of the aspects described herein, one, two or moreamino acid mutations (i.e., substitutions, insertions or deletions) areintroduced into an IgG constant domain, or FcRn-binding fragment thereof(preferably an Fc or hinge-Fc domain fragment) to decrease the half-lifeof the anti-LAP antibody in vivo. In some embodiments of the aspectsdescribed herein, one, two or more amino acid mutations (i.e.,substitutions, insertions or deletions) are introduced into an IgGconstant domain, or FcRn-binding fragment thereof (preferably an Fc orhinge-Fc domain fragment) to increase the half-life of the antibody invivo. In some embodiments of the aspects described herein, theantibodies can have one or more amino acid mutations (e.g.,substitutions) in the second constant (CH2) domain (residues 231-340 ofhuman IgG1) and/or the third constant (CH3) domain (residues 341-447 ofhuman IgG1), with numbering according to the EU index in Kabat (Kabat EA et al., (1991) supra). In some embodiments of the aspects describedherein, the constant region of the IgG1 of an antibody orantigen-binding fragment thereof described herein comprises a methionine(M) to tyrosine (Y) substitution in position 252, a serine (S) tothreonine (T) substitution in position 254, and a threonine (T) toglutamic acid (E) substitution in position 256, numbered according tothe EU index as in Kabat. See U.S. Pat. No. 7,658,921, which isincorporated herein by reference. This type of mutant IgG, referred toas “YTE mutant” has been shown to display fourfold increased half-lifeas compared to wild-type versions of the same antibody (see Dall'Acqua WF et al., (2006) J Biol Chem 281: 23514-24). In some embodiments of theaspects described herein, an antibody or antigen-binding fragmentthereof comprises an IgG constant domain comprising one, two, three ormore amino acid substitutions of amino acid residues at positions251-257, 285-290, 308-314, 385-389, and 428-436, numbered according tothe EU index as in Kabat.

In some embodiments of the aspects described herein, one, two or moreamino acid substitutions are introduced into an IgG constant domain Fcregion to alter the effector function(s) of the anti-LAP antibody. Forexample, one or more amino acids selected from amino acid residues 234,235, 236, 237, 297, 318, 320 and 322, numbered according to the EU indexas in Kabat, can be replaced with a different amino acid residue suchthat the antibody has an altered affinity for an effector ligand butretains the antigen-binding ability of the parent antibody. The effectorligand to which affinity is altered can be, for example, an Fc receptoror the C1 component of complement. This approach is described in furtherdetail in U.S. Pat. Nos. 5,624,821 and 5,648,260. In some embodiments ofthe aspects described herein, the deletion or inactivation (throughpoint mutations or other means) of a constant region domain can reduceFc receptor binding of the circulating antibody thereby increasing tumorlocalization. See, e.g., U.S. Pat. Nos. 5,585,097 and 8,591,886 for adescription of mutations that delete or inactivate the constant domainand thereby increase tumor localization. In some embodiments of theaspects described herein, one or more amino acid substitutions may beintroduced into the Fc region of an antibody described herein to removepotential glycosylation sites on Fc region, which may reduce Fc receptorbinding (see, e.g., Shields R L et al., (2001) J Biol Chem 276:6591-604). In some embodiments of the aspects described herein, one ormore of the following mutations in the constant region of an antibodydescribed herein can be made: an N297A substitution; an N297Qsubstitution; a L235A substitution and a L237A substitution; a L234Asubstitution and a L235A substitution; a E233P substitution; a L234Vsubstitution; a L235A substitution; a C236 deletion; a P238Asubstitution; a D265A substitution; a A327Q substitution; or a P329Asubstitution, numbered according to the EU index as in Kabat. In someembodiments of the aspects described herein, an antibody orantigen-binding fragment thereof described herein comprises the constantdomain of an IgG1 with an N297Q or N297A amino acid substitution.

In some embodiments of the aspects described herein, one or more aminoacids selected from amino acid residues 329, 331 and 322 in the constantregion of an anti-LAP antibody described herein, numbered according tothe EU index as in Kabat, can be replaced with a different amino acidresidue such that the antibody has altered C1q binding and/or reduced orabolished complement dependent cytotoxicity (CDC). This approach isdescribed in further detail in U.S. Pat. No. 6,194,551 (Idusogie et al).In some embodiments of the aspects described herein, one or more aminoacid residues within amino acid positions 231 to 238 in the N-terminalregion of the CH2 domain of an antibody described herein are altered tothereby alter the ability of the antibody to fix complement. Thisapproach is described further in International Publication No. WO94/29351. In some embodiments of the aspects described herein, the Fcregion of an antibody described herein is modified to increase theability of the antibody to mediate antibody dependent cellularcytotoxicity (ADCC) and/or to increase the affinity of the antibody foran Fcγ receptor by mutating one or more amino acids (e.g., introducingamino acid substitutions) at the following positions: 238, 239, 248,249, 252, 254, 255, 256, 258, 265, 267, 268, 269, 270, 272, 276, 278,280, 283, 285, 286, 289, 290, 292, 293, 294, 295, 296, 298, 301, 303,305, 307, 309, 312, 315, 320, 322, 324, 326, 327, 329, 330, 331, 333,334, 335, 337, 338, 340, 360, 373, 376, 378, 382, 388, 389, 398, 414,416, 419, 430, 434, 435, 437, 438 or 439, numbered according to the EUindex as in Kabat. This approach is described further in InternationalPublication No. WO 00/42072.

In some embodiments of the aspects described herein, an anti-LAPantibody described herein comprises the constant region of an IgG4antibody and the serine at amino acid residue 228 of the heavy chain,numbered according to the EU index as in Kabat, is substituted forproline.

Antibodies with reduced fucose content have been reported to have anincreased affinity for Fc receptors, such as, e.g., FcγRIIIa.Accordingly, in certain embodiments, the anti-LAP antibodies orantigen-binding fragments thereof described herein have reduced fucosecontent or no fucose content. Such antibodies can be produced usingtechniques known to one skilled in the art. For example, the antibodiescan be expressed in cells deficient or lacking the ability offucosylation. In a specific example, cell lines with a knockout of bothalleles of α1,6-fucosyltransferase can be used to produce antibodieswith reduced fucose content. The POTELLIGENTR™ system (Lonza) is anexample of such a system that can be used to produce antibodies withreduced fucose content. Alternatively, antibodies or antigen-bindingfragments with reduced fucose content or no fucose content can beproduced by, e.g.: (i) culturing cells under conditions which prevent orreduce fucosylation; (ii) posttranslational removal of fucose (e.g.,with a fucosidase enzyme); (iii) post-translational addition of thedesired carbohydrate, e.g., after recombinant expression of anon-glycosylated glycoprotein; or (iv) purification of the glycoproteinso as to select for antibodies or antigen-binding fragments thereofwhich are not fucsoylated. See, e.g., Longmore G D & Schachter H (1982)Carbohydr Res 100: 365-92 and Imai-Nishiya H et al., (2007) BMCBiotechnol. 7: 84 for methods for producing antibodies orantigen-binding fragments thereof with no fucose content or reducedfucose content.

In some embodiments of the aspects described herein, anti-LAP antibodiesor antigen-binding fragments thereof described herein have an increasedaffinity for CD32B (also known as FcγRIIB or FCGR2B), e.g., as comparedto an antibody with a wild-type Fc region, e.g., an IgG1 Fc. In someembodiments of the aspects described herein, anti-LAP antibodies orantigen-binding fragments thereof described herein have a selectivelyincreased affinity for CD32B (FcγRIIB) over both CD32A (FcγRIIA) andCD16 (FcγRIIIA) Sequence alterations that result in increased affinityfor CD32B are provided, for example, in Mimoto et al., ProteinEngineering, Design & Selection 10: 589-598 (2013), Chu et al.,Molecular Immunology 45: 3926-3933 (2008), and Strohl, Current Opinionin Biology 20: 685-691 (2009), each of which is herein incorporated byreference in its entirety. In some embodiments of the aspects describedherein, the antibody or antigen-binding fragment with an increasedaffinity for CD32B comprises a heavy chain constant region, e.g., anIgG1 constant region, or fragment thereof comprising a mutation selectedfrom the group consisting of: G236D, P238D, S239D, S267E, L328F, L328E,an arginine inserted after position 236, and combinations thereof,numbered according to EU index (Kabat et al., Sequences of Proteins ofImmunological Interest, U.S. Department of Health and Human Services,Bethesda (1991)). In some embodiments of the aspects described herein,the antibody or antigen-binding fragment with an increased affinity forCD32B comprises a heavy chain constant region, e.g., an IgG1 constantregion, or fragment thereof comprising S267E and L328F substitutions. Insome embodiments of the aspects described herein, the antibody orantigen-binding fragment with an increased affinity for CD32B comprisesa heavy chain constant region, e.g., an IgG1 constant region, orfragment thereof comprising P238D and L328E substitutions. In someembodiments of the aspects described herein, the antibody orantigen-binding fragment with an increased affinity for CD32B comprisesa heavy chain constant region, e.g., an IgG1 constant region, orfragment thereof comprising a P238D substitution and substitutionselected from the group consisting of E233D, G237D, H268D, P271G, A330R,and combinations thereof. In some embodiments of the aspects describedherein, the antibody or antigen-binding fragment with an increasedaffinity for CD32B comprises a heavy chain constant region, e.g., anIgG1 constant region, or fragment thereof comprising P238D, E233D,G237D, H268D, P271G, and A330R substitutions. In some embodiments of theaspects described herein, the antibody or antigen-binding fragment withan increased affinity for CD32B comprises a heavy chain constant region,e.g., an IgG1 constant region, or fragment thereof comprising G236D andS267E. In some embodiments of the aspects described herein, the antibodyor antigen-binding fragment with an increased affinity for CD32Bcomprises a heavy chain constant region, e.g., an IgG1 constant region,or fragment thereof comprising S239D and S267E. In some embodiments ofthe aspects described herein, the antibody or antigen-binding fragmentwith an increased affinity for CD32B comprises a heavy chain constantregion, e.g., an IgG1 constant region, or fragment thereof comprisingS267E and L328F. In some embodiments of the aspects described herein,the antibody or antigen-binding fragment with an increased affinity forCD32B comprises a heavy chain constant region, e.g., an IgG1 constantregion, or fragment thereof comprising an arginine inserted afterposition 236 and L328R.

In some embodiments of the aspects described herein, an anti-LAPantibody or antigen-binding fragment thereof that specifically binds toLAP (e.g., human LAP) comprises VL framework regions (FRs) having atleast 80%, at least 85%, at least 90%, at least 95%, or at least 98%sequence identity to one, two, three, or four of the VL frameworkregions described herein as SEQ ID NOs: 21-24. In some embodiments ofthe aspects described herein, an anti-LAP antibody or antigen-bindingfragment thereof that specifically binds to LAP (e.g., human LAP)comprises VH framework regions (FRs) having at least 80%, at least 85%,at least 90%, at least 95%, or at least 98% sequence identity to one,two, three, or four of the VH framework regions described herein as SEQID NOs: 17-20. In some embodiments of the aspects described herein, anantibody or antigen-binding fragment thereof that specifically binds toLAP (e.g., human LAP) comprises (i) VH framework regions (FRs) having atleast 80%, at least 85%, at least 90%, at least 95%, or at least 98%sequence identity to one, two, three, or four of the VH frameworkregions described herein as SEQ ID NOs: 17-20, and (ii) VL frameworkregions (FRs) having at least 80%, at least 85%, at least 90%, at least95%, or at least 98% sequence identity to one, two, three, or four ofthe VL framework regions described herein as SEQ ID NOs: 21-24.

The determination of percent identity between two sequences (e.g., aminoacid sequences or nucleic acid sequences) can also be accomplished usinga mathematical algorithm. A specific, non-limiting example of amathematical algorithm utilized for the comparison of two sequences isthe algorithm of Karlin S & Altschul S F (1990) PNAS 87: 2264-2268,modified as in Karlin S & Altschul S F (1993) PNAS 90: 5873-5877. Suchan algorithm is incorporated into the NBLAST and XBLAST programs ofAltschul S F et al., (1990) J Mol Biol 215: 403. BLAST nucleotidesearches can be performed with the NBLAST nucleotide program parametersset, e.g., for score=100, wordlength=12 to obtain nucleotide sequenceshomologous to a nucleic acid molecule described herein. BLAST proteinsearches can be performed with the XBLAST program parameters set, e.g.,to score 50, wordlength=3 to obtain amino acid sequences homologous to aprotein molecule described herein. To obtain gapped alignments forcomparison purposes, Gapped BLAST can be utilized as described inAltschul S F et al., (1997) Nuc Acids Res 25: 3389 3402. Alternatively,PSI BLAST can be used to perform an iterated search which detectsdistant relationships between molecules (Id.). When utilizing BLAST,Gapped BLAST, and PSI Blast programs, the default parameters of therespective programs (e.g., of XBLAST and NBLAST) can be used (see, e.g.,National Center for Biotechnology Information (NCBI) on the worldwideweb, ncbi.nlm.nih.gov). Another specific, non limiting example of amathematical algorithm utilized for the comparison of sequences is thealgorithm of Myers and Miller, 1988, CABIOS 4:11 17. Such an algorithmis incorporated in the ALIGN program (version 2.0) which is part of theGCG sequence alignment software package. When utilizing the ALIGNprogram for comparing amino acid sequences, a PAM120 weight residuetable, a gap length penalty of 12, and a gap penalty of 4 can be used.The percent identity between two sequences can be determined usingtechniques similar to those described above, with or without allowinggaps. In calculating percent identity, typically only exact matches arecounted.

In some aspects, provided herein are anti-LAP antibodies orantigen-binding fragments thereof that bind the same or an overlappingepitope of LAP (e.g., an epitope of human LAP) as any one of theantibodies produced by hybridomas TW4-9E7, TW4-5A8, TW4-3E5, TW4-4E5,TW4-12B12, TW4-13B12, TW4-1G12, TW4-3G5, TW4-2F8, TW4-6H10, TW4-1G2,TW4-1E1, TW4-16F4, TW4-8F10, TW4-3H6, TW4-2C9, TW7-16B4, TW7-28G11,TW7-7H4, and TW7-20B9. In some embodiments of these aspects, theanti-LAP antibodies or antigen-binding fragments thereof bind the sameor overlapping epitope of LAP as the antibody produced by hybridomaTW7-28G11 having a V_(H) domain of SEQ ID NO: 8 and a V_(L) domain ofSEQ ID NO: 13. As known to one of ordinary skill in the art, the epitopeof an antibody can be determined by, e.g., NMR spectroscopy, X-raydiffraction crystallography studies, ELISA assays, hydrogen/deuteriumexchange coupled with mass spectrometry (e.g., liquid chromatographyelectrospray mass spectrometry), array-based oligo-peptide scanningassays, and/or mutagenesis mapping (e.g., site-directed mutagenesismapping). For X-ray crystallography, crystallization can be accomplishedusing any of the known methods in the art (e.g., Giege R et al., (1994)Acta Crystallogr D Biol Crystallogr 50(Pt 4): 339-350; McPherson A(1990) Eur J Biochem 189: 1-23; Chayen N E (1997) Structure 5:1269-1274; McPherson A (1976) J Biol Chem 251: 6300-6303).Antibody:antigen crystals can be studied using well known X-raydiffraction techniques and can be refined using computer software suchas X-PLOR (Yale University, 1992, distributed by Molecular Simulations,Inc.; see e.g. Meth Enzymol (1985) volumes 114 & 115, eds Wyckoff H W etal., U.S. Patent Application No. 2004/0014194), and BUSTER (Bricogne G(1993) Acta Crystallogr D Biol Crystallogr 49(Pt 1): 37-60; Bricogne G(1997) Meth Enzymol 276A: 361-423, ed Carter C W; Roversi P et al.,(2000) Acta Crystallogr D Biol Crystallogr 56(Pt 10): 1316-1323).Mutagenesis mapping studies may be accomplished using any method knownto one of skill in the art. See, e.g., Champe M et al., (1995) supra andCunningham B C & Wells J A (1989) supra for a description of mutagenesistechniques, including alanine scanning mutagenesis techniques. Inaddition, antibodies that recognize and bind to the same or overlappingepitopes of LAP (e.g., human LAP) can be identified using routinetechniques such as an immunoassay, for example, by showing the abilityof one antibody to block the binding of another antibody to a targetantigen, i.e., a competitive binding assay. Competition binding assaysalso can be used to determine whether two antibodies have similarbinding specificity for an epitope. Competitive binding can bedetermined in an assay in which the immunoglobulin under test inhibitsspecific binding of a reference antibody to a common antigen, such asLAP. Numerous types of competitive binding assays are known, forexample: solid phase direct or indirect radioimmunoassay (RIA), solidphase direct or indirect enzyme immunoassay (EIA), sandwich competitionassay (see Stahli C et al., (1983) Methods Enzymol 9: 242-253); solidphase direct biotin-avidin EIA (see Kirkland T N et al., (1986) JImmunol 137: 3614-9); solid phase direct labeled assay, solid phasedirect labeled sandwich assay (see Harlow E & Lane D, (1988) Antibodies:A Laboratory Manual, Cold Spring Harbor Press); solid phase direct labelRIA using 1-125 label (see Morel G A et al., (1988) Mol Immunol 25(1):7-15); solid phase direct biotin-avidin EIA (Cheung R C et al., (1990)Virology 176: 546-52); and direct labeled RIA. (Moldenhauer G et al.,(1990) Scand J Immunol 32: 77-82). Typically, such an assay involves theuse of purified antigen (e.g., LAP) bound to a solid surface or cellsbearing either of these, an unlabeled test immunoglobulin and a labeledreference immunoglobulin. Competitive inhibition can be measured bydetermining the amount of label bound to the solid surface or cells inthe presence of the test immunoglobulin. Usually the test immunoglobulinis present in excess. Usually, when a competing antibody is present inexcess, it will inhibit specific binding of a reference antibody to acommon antigen by at least 50-55%, 55-60%, 60-65%, 65-70% 70-75% ormore. A competition binding assay can be configured in a large number ofdifferent formats using either labeled antigen or labeled antibody. In acommon version of this assay, the antigen is immobilized on a 96-wellplate. The ability of unlabeled antibodies to block the binding oflabeled antibodies to the antigen is then measured using radioactive orenzyme labels. For further details see, for example, Wagener C et al.,(1983) J Immunol 130: 2308-2315; Wagener C et al., (1984) J ImmunolMethods 68: 269-274; Kuroki M et al., (1990) Cancer Res 50: 4872-4879;Kuroki M et al., (1992) Immunol Invest 21: 523-538; Kuroki M et al.,(1992) Hybridoma 11: 391-407 and Antibodies: A Laboratory Manual, EdHarlow E & Lane D editors supra, pp. 386-389. A competition assay can beperformed, for example, using surface plasmon resonance (BIACORE) e.g.,by an ‘in tandem approach’ such as that described by Abdiche Y N et al.,(2009) Analytical Biochem 386: 172-180, whereby LAP antigen isimmobilized on the chip surface, for example, a CMS sensor chip and theanti-LAP antibodies are then run over the chip. To determine if anantibody competes with an anti-LAP antibody or antigen-binding fragmentthereof described herein, the anti-LAP antibody is first run over thechip surface to achieve saturation and then the potential, competingantibody is added. Binding of the competing antibody can then bedetermined and quantified relative to a non-competing control.

Competition binding assays can be used to determine whether an antibodyis competitively blocked, e.g., in a dose dependent manner, by anotherantibody for example, an antibody that binds essentially the sameepitope, or overlapping epitopes, as a reference antibody, when the twoantibodies recognize identical or sterically overlapping epitopes incompetition binding assays such as competition ELISA assays, which canbe configured in all number of different formats, using either labeledantigen or labeled antibody.

Accordingly, in some embodiments of the aspects described herein, ananti-LAP antibody can be tested in competition binding assays with anyone of the antibodies produced by hybridomas TW4-9E7, TW4-5A8, TW4-3E5,TW4-4E5, TW4-12B12, TW4-13B12, TW4-1G12, TW4-3G5, TW4-2F8, TW4-6H10,TW4-1G2, TW4-1E1, TW4-16F4, TW4-8F10, TW4-3H6, TW4-2C9, TW7-16B4,TW7-28G11, TW7-7H4, and TW7-20B9 described herein, or a chimeric or Fabantibody thereof, or an anti-LAP antibody comprising one or more V_(H)CDRs and one or more V_(L) CDRs of any one of the antibodies produced byhybridomas TW4-9E7, TW4-5A8, TW4-3E5, TW4-4E5, TW4-12B12, TW4-13B12,TW4-1G12, TW4-3G5, TW4-2F8, TW4-6H10, TW4-1G2, TW4-1E1, TW4-16F4,TW4-8F10, TW4-3H6, TW4-2C9, TW7-16B4, TW7-28G11, TW7-7H4, and TW7-20B9described herein.

In some embodiments of the methods described herein, the LAP bindingagent is a chimeric antibody derivative of an anti-LAP antibody orantigen-binding fragment thereof that specifically binds LAP.

As used herein, the term “chimeric antibody” refers to an antibodymolecule in which a portion of the heavy and/or light chain is identicalwith or homologous to corresponding sequences in antibodies derived froma particular species or belonging to a particular antibody class orsubclass, while the remainder of the chain(s) is identical with orhomologous to corresponding sequences in antibodies derived from anotherspecies or belonging to another antibody class or subclass, as well asfragments of such antibodies, so long as they exhibit the desiredbiological activity (U.S. Pat. No. 4,816,567; and Morrison et al., Proc.Natl. Acad. Sci. USA 81:6851-6855 (1984)). Chimeric antibody moleculescan include, for example, one or more V_(H) and/or V_(L) antigen bindingdomains from an antibody of a mouse, rat, or other species, with humanconstant regions. A variety of approaches for making chimeric antibodieshave been described and can be used to make chimeric antibodiescontaining the immunoglobulin variable region which recognizes thedesired antigen, e.g., LAP. See, for example, Takeda et al., 1985,Nature 314:452; Cabilly et al., U.S. Pat. No. 4,816,567; Boss et al.;Tanaguchi et al., European Patent Publication EP171496; European PatentPublication 0173494, United Kingdom patent GB 2177096B).

In some embodiments of the methods described herein, the LAP bindingagent is a CDR-grafted antibody derivative of an anti-LAP antibody orantigen-binding fragment thereof that specifically binds LAP.

The term “CDR-grafted antibody” refers to antibodies which compriseheavy and light chain variable region sequences from one species, but inwhich the sequences of one or more of the CDR regions of V_(H) and/orV_(L) are replaced with CDR sequences of another species, such asantibodies having human heavy and light chain variable regions in whichone or more of the human CDRs (e.g., CDR3) has been replaced with mouseCDR sequences. CDR-grafted antibodies described herein comprise heavyand light chain variable region sequences from a human antibody whereinone or more of the CDR regions of V_(H) and/or V_(L) are replaced withCDR sequences of the murine antibodies described herein, such as SEQ IDNOs: 9-11 and 14-16, or the CDR sequences of any one of the antibodiesproduced by hybridomas TW4-9E7, TW4-5A8, TW4-3E5, TW4-4E5, TW4-12B12,TW4-13B12, TW4-1G12, TW4-3G5, TW4-2F8, TW4-6H10, TW4-1G2, TW4-1E1,TW4-16F4, TW4-8F10, TW4-3H6, TW4-2C9, TW7-16B4, TW7-28G11, TW7-7H4, andTW7-20B9. A framework sequence from any human antibody can serve as thetemplate for CDR grafting. However, straight chain replacement onto sucha framework often leads to some loss of binding affinity to the antigen.The more homologous a human antibody is to the original non-human, ormurine antibody, the less likely the possibility that combining thenon-human CDRs with the human framework will introduce distortions inthe CDRs that could reduce affinity. Therefore, the human variableframework chosen to replace the murine variable framework apart from theCDRs have, for example, at least a 65% sequence identity with the murineantibody variable region framework. The human and murine variableregions apart from the CDRs have, for example, at least 70% sequenceidentity, at least 75% sequence identity, at least 80% sequenceidentity, or at least 85% sequence identity. Methods for producingchimeric antibodies are known in the art. (See, for example, EP 239,400;PCT publication WO 91/09967; U.S. Pat. Nos. 5,225,539; 5,530,101; and5,585,089), veneering or resurfacing (EP 592,106; EP 519,596; Padlan,Molecular Immunology 28(4/5):489-498 (1991); Studnicka et al., ProteinEngineering 7(6):805-814 (1994); Roguska et al., PNAS 91:969-973(1994)), and chain shuffling (U.S. Pat. No. 5,565,352), the contents ofeach of which are herein incorporated by reference in their entireties.

In some embodiments of the methods described herein, the LAP bindingagent is a humanized antibody derivative of an anti-LAP antibody orantigen-binding fragment thereof that specifically binds LAP.

Humanized forms of non-human (e.g., murine) antibodies are chimericantibodies which contain minimal sequence derived from non-humanimmunoglobulin. For the most part, humanized antibodies are humanimmunoglobulins (recipient antibody) in which residues from a CDR orhypervariable region of the recipient are replaced by residues from aCDR or hypervariable region of a non-human species (donor antibody) suchas mouse, rat, rabbit or nonhuman primate having the desiredspecificity, affinity, and capacity. In some instances, Fv frameworkregion (FR) residues of the human immunoglobulin are replaced bycorresponding non-human residues. Furthermore, humanized antibodies cancomprise residues which are not found in the recipient antibody or inthe donor antibody. These modifications are made to further refineantibody performance. In general, the humanized antibody will comprisesubstantially all of at least one, and typically two, variable domains,in which all or substantially all of the hypervariable loops correspondto those of a non-human immunoglobulin and all or substantially all ofthe FR regions are those of a human immunoglobulin consensus sequence.The humanized antibody optionally also will comprise at least a portionof an immunoglobulin constant region (Fc), typically that of a humanimmunoglobulin. For further details, see Jones et al., Nature321:522-525 (1986); Riechmann et al., Nature 332:323-329 (1988); andPresta, Curr. Op. Struct. Biol. 2:593-596 (1992).

The humanized antibody can be selected from any class ofimmunoglobulins, including IgM, IgG, IgD, IgA and IgE, and any subclass,including without limitation IgG1, IgG2, IgG3 and IgG4.

The framework and CDR regions of a humanized antibody need notcorrespond precisely to the parental sequences, e.g., the donor antibodyCDR or the consensus framework can be mutagenized by substitution,insertion and/or deletion of at least one amino acid residue so that theCDR or framework residue at that site does not correspond exactly toeither the donor antibody or the consensus framework. In preferredembodiments, such mutations, however, will not be extensive. Usually, atleast 80%, preferably at least 85%, more preferably at least 90%, andmost preferably at least 95% of the humanized antibody residues willcorrespond to those of the parental FR and CDR sequences. As usedherein, the term “consensus framework” refers to the framework region inthe consensus immunoglobulin sequence. As used herein, the term“consensus immunoglobulin sequence” refers to the sequence formed fromthe most frequently occurring amino acids (or nucleotides) in a familyof related immunoglobulin sequences (see e.g., Winnaker, From Genes toClones (Veriagsgesellschaft, Weinheim, Germany 1987). In a family ofimmunoglobulins, each position in the consensus sequence is occupied bythe amino acid occurring most frequently at that position in the family.Where two amino acids occur equally frequently, either can be includedin the consensus sequence.

As used herein, “Vernier zone” refers to a subset of framework residuesthat may adjust CDR structure and fine-tune the fit to antigen asdescribed by Foote and Winter (1992, J. Mol. Biol. 224:487-499, which isincorporated herein by reference). Vernier zone residues form a layerunderlying the CDRs and can impact on the structure of CDRs and theaffinity of the antibody.

Known human immunoglobulin (Ig) sequences that can be used with the CDRsequences described herein are disclosed, for example, on the worldwideweb at www.ncbi.nlm.nih.gov/entrez-/query.fcgi;www.atcc.org/phage/hdb.html; www.sciquest.com/; www.abcam.com/;www.antibodyresource.com/onlinecomp.html;www.public.iastate.eduLabout.pedro/research_tools.html;www.mgen.uniheidelberg.de/SD/IT/IT.html;www.whfreeman.com/immunology/CH-05/kuby05.htm;www.library.thinkquest.org/12429/Immune/Antibody.html;www.hhmi.org/grants/lectures/1996/vlab/;www.path.cam.ac.uk/.about.mrc7/m-ikei-mages.html;www.antibodyresource.com/; mcb.harvard.edu/BioLinks/Immunology.html.www.immunologylink com/; pathbox.wustl.edu/.about.hcenter/index.-html;www.biotech.ufl.eduLabout.hcl/; www.pebio.com/pa/340913/340913.html-;www.nal.usda.gov/awic/pubs/antibody/;www.m.ehime-u.acjp/.about.yasuhito-/Elisa.html;www.biodesign.com/table.asp; www.icnet.uk/axp/facs/davies/lin-ks.html;www.biotech.ufl.eduLabout.fccl/protocol.html;www.isac-net.org/sites_geo.html;aximtl.imt.uni-marburg.de/.about.rek/AEP-Start.html;baserv.uci.kun.nl/.about.jraats/linksl html;www.recab.uni-hd.de/immuno.bme.nwu.edu/;www.mrc-cpe.cam.ac.uk/imt-doc/pu-blic/INTRO.html;www.ibt.unam.mx/virN_mice.html; imgt.cnusc.fr:8104/;www.biochem.ucl.ac.uk/.about.martin/abs/index.html;anti-body.bath.ac.uk/; abgen.cvm.tamu.edu/lab/wwwabgen.html;www.unizh.chLabouthonegger/AHOsem-inar/Slide01.html;www.cryst.bbk.ac.uk/.about.ubcg07s/; www.nimrmrc.ac.uk/CC/ccaewg/ccaewg.htm;www.path.cam.ac.ukhabout.mrc7/h-umanisation/TAHHP.html;www.ibt.unam.na/vir/structure/stat_aim.html;www.biosci.missouri.edu/smithgp/index.html;www.cryst.bioc.cam.ac.uk/.abo-utimolina/Web-pages/Pept/spottech.html;www.jerini.de/fr roducts.htm; www.patents.ibm.com/ibm.html.Kabat et al.,Sequences of Proteins of Immunological Interest, U.S. Dept. Health(1983), each entirely incorporated herein by reference. Such importedsequences can be used to reduce immunogenicity or reduce, enhance ormodify binding, affinity, on-rate, off-rate, avidity, specificity,half-life, or any other suitable characteristic, as known in the art.

Framework residues in the human framework regions can be substitutedwith the corresponding residue from the CDR donor antibody to alter,preferably improve, antigen binding. These framework substitutions areidentified by methods well known in the art, e.g., by modeling of theinteractions of the CDR and framework residues to identify frameworkresidues important for antigen binding and sequence comparison toidentify unusual framework residues at particular positions. (See, e.g.,Queen et al., U.S. Pat. No. 5,585,089; Riechmann et al., Nature 332:323(1988), which are incorporated herein by reference in their entireties.)Three-dimensional immunoglobulin models are commonly available and arefamiliar to those skilled in the art. Computer programs are availablewhich illustrate and display probable three-dimensional conformationalstructures of selected candidate immunoglobulin sequences. Inspection ofthese displays permits analysis of the likely role of the residues inthe functioning of the candidate immunoglobulin sequence, i.e., theanalysis of residues that influence the ability of the candidateimmunoglobulin to bind its antigen. In this way, FR residues can beselected and combined from the consensus and import sequences so thatthe desired antibody characteristic, such as increased affinity for thetarget antigen(s), is achieved. In general, the CDR residues aredirectly and most substantially involved in influencing antigen binding.Antibodies can be humanized using a variety of techniques known in theart, including, but not limited to, those described in Jones et al.,Nature 321:522 (1986); Verhoeyen et al., Science 239:1534 (1988), Simset al., J. Immunol. 151: 2296 (1993); Chothia and Lesk, J. Mol. Biol.196:901 (1987), Carter et al., Proc. Natl. Acad. Sci. U.S.A. 89:4285(1992); Presta et al., J. Immunol. 151:2623 (1993), Padlan, MolecularImmunology 28(4/5):489-498 (1991); Studnicka et al., Protein Engineering7(6):805-814 (1994); Roguska. et al., PNAS 91:969-973 (1994); PCTpublication WO 91/09967, PCT/: US98/16280, US96/18978, US91/09630,US91/05939, US94/01234, GB89/01334, GB91/01134, GB92/01755; WO90/14443,WO90/14424, WO90/14430, EP 229246, EP 592,106; EP 519,596, EP 239,400,U.S. Pat. Nos. 5,565,332, 5,723,323, 5,976,862, 5,824,514, 5,817,483,5,814,476, 5,763,192, 5,723,323, 5,766,886, 5,714,352, 6,204,023,6,180,370, 5,693,762, 5,530,101, 5,585,089, 5,225,539; 4,816,567, eachentirely incorporated herein by reference.

As used herein, the terms “acceptor” and “acceptor antibody” refer tothe antibody or nucleic acid sequence providing or encoding at least80%, at least 85%, at least 90%, at least 95%, at least 98% or 100% ofthe amino acid sequences of one or more of the framework regions. Insome embodiments, the term acceptor” refers to the antibody amino acidor nucleic acid sequence providing or encoding the constant region(s).In yet another embodiment, the term “acceptor” refers to the antibodyamino acid or nucleic acid sequence providing or encoding one or more ofthe framework regions and the constant region(s). In a specificembodiment, the term “acceptor” refers to a human antibody amino acid ornucleic acid sequence that provides or encodes at least 80%, preferably,at least 85%, at least 90%, at least 95%, at least 98 or 100% of theamino acid sequences of one or more of the framework regions. Inaccordance with this embodiment, an acceptor may contain at least 1, atleast 2, at least 3, least 4, at least 5, or at least 10 amino acidresidues not occurring at one or more specific positions of a humanantibody. An acceptor framework region and/or acceptor constantregion(s) may be, e.g., derived or obtained from a germline antibodygene, a mature antibody gene, a functional antibody (e.g., antibodieswell-known in the art, antibodies in development, or antibodiescommercially available).

As used herein, the term “canonical” residue refers to a residue in aCDR or framework that defines a particular canonical CDR structure asdefined by Chothia et al. (J. Mol. Biol. 196:901-907 (1987); Chothia etal., J. Mol. Biol, 227:799 (1992), both are incorporated herein byreference). According to Chothia et al., critical portions of the CDRsof many antibodies have nearly identical peptide backbone confirmationsdespite great diversity at the level of amino acid sequence. Eachcanonical structure specifies primarily a set of peptide backbonetorsion angles for a contiguous segment of amino acid residues forming aloop.

As used herein, the terms “donor” and “donor antibody” refer to anantibody providing one or more CDRs. In some embodiments of thecompositions and methods described herein, the donor antibody is anantibody from a species different from the antibody from which theframework regions are obtained or derived. In the context of a humanizedantibody, the term “donor antibody” refers to a non-human antibodyproviding one or more CDRs.

As used herein, the term “key” residues refers to certain residueswithin the variable region that more impact on the binding specificityand/or affinity of an antibody, in particular a humanized antibody. Akey residue includes, but is not limited to, one or more of thefollowing: a residue that is adjacent to a CDR, a potentialglycosylation site (which can be either N- or O-glycosylation site), arare residue, a residue capable of interacting with the antigen, aresidue capable of interacting with a CDR, a canonical residue, acontact residue between heavy chain variable region and light chainvariable region, a residue within the Vernier zone, and a residue in theregion that overlaps between the Chothia definition of a variable heavychain CDR1 and the Kabat definition of the first heavy chain framework.

In some embodiments of the compositions and methods comprising any ofthe anti-LAP antibodies or antigen-binding fragments thereof describedherein, the anti-LAP antibody or antigen-binding fragment is an antibodyderivative. For example, but not by way of limitation, antibodyderivatives include antibodies that have been modified, e.g., byglycosylation, acetylation, pegylation, phosphorylation, amidation,derivatization by known protecting/blocking groups, proteolyticcleavage, linkage to a cellular ligand or other protein, etc. Any ofnumerous chemical modifications can be carried out by known techniques,including, but not limited to specific chemical cleavage, acetylation,formylation, etc. Additionally, the derivative can contain one or morenon-classical amino acids.

The anti-LAP antibodies and antigen-binding fragments thereof describedherein can be generated by any suitable method known in the art.Monoclonal and polyclonal antibodies against, for example, LAP, areknown in the art. To the extent necessary, e.g., to generate antibodieswith particular characteristics or epitope specificity, the skilledartisan can generate new monoclonal or polyclonal anti-LAP antibodies asbriefly discussed herein or as known in the art.

Polyclonal antibodies can be produced by various procedures well knownin the art. For example, LAP or fragments thereof comprising one or moreof the LAP ligand interaction sites, can be administered to various hostanimals including, but not limited to, rabbits, mice, rats, etc. toinduce the production of sera containing polyclonal antibodies specificfor the protein. Polyclonal antibodies are preferably raised in animalsby multiple subcutaneous (sc) or intraperitoneal (ip) injections of therelevant antigen and an adjuvant. It can be useful to conjugate theantigen to a protein that is immunogenic in the species to be immunized,e.g., keyhole limpet hemocyanin, serum albumin, bovine thyroglobulin, orsoy-bean trypsin inhibitor using a bifunctional or derivatizing agent,for example, maleimidobenzoyl sulfosuccinimide ester (conjugationthrough cysteine residues), N-hydroxy-succinimide (through lysineresidues), glutaraldehyde, succinic anhydride, SOCl₂, or R¹N═C═NR, whereR and R¹ are different alkyl groups. Various other adjuvants can be usedto increase the immunological response, depending on the host species,and include but are not limited to, Freund's (complete and incomplete),mineral gels such as aluminum hydroxide, surface active substances suchas lysolecithin, pluronic polyols, polyanions, peptides, oil emulsions,keyhole limpet hemocyanins, dinitrophenol, and potentially useful humanadjuvants such as BCG (bacille Calmette-Guerin) and Corynebacteriumparvum. Suitable adjuvants are also well known to one of skill in theart.

Monoclonal antibodies can be prepared using a wide variety of techniquesknown in the art including the use of hybridoma, recombinant, and phagedisplay technologies, or a combination thereof. Various methods formaking monoclonal antibodies described herein are available in the art.For example, the monoclonal antibodies can be made using the hybridomamethod first described by Kohler et al., Nature, 256:495 (1975), or anylater developments thereof, or by recombinant DNA methods (U.S. Pat. No.4,816,567). For example, monoclonal antibodies can be produced usinghybridoma techniques including those known in the art and taught, forexample, in Harlow et al., Antibodies: A Laboratory Manual, (Cold SpringHarbor Laboratory Press, 2nd ed., 1988); Hammer-ling, et al., in:Monoclonal Antibodies and T-Cell Hybridomas 563-681 (Elsevier, N.Y.,1981) (said references incorporated by reference in their entireties).Methods for producing and screening for specific antibodies usinghybridoma technology are routine and well known in the art. In anotherexample, antibodies useful in the methods and compositions describedherein can also be generated using various phage display methods knownin the art, such as isolation from antibody phage libraries generatedusing the techniques described in McCafferty et al., Nature, 348:552-554(1990). Clackson et al., Nature, 352:624-628 (1991) and Marks et al., J.Mol. Biol., 222:581-597 (1991) describe the isolation of murine andhuman antibodies, respectively, using phage libraries. Subsequentpublications describe the production of high affinity (nM range) humanantibodies by chain shuffling (Marks et al., Bio/Technology, 10:779-783(1992)), as well as combinatorial infection and in vivo recombination asa strategy for constructing very large phage libraries (Waterhouse etal., Nuc. Acids. Res., 21:2265-2266 (1993)). Thus, these techniques areviable alternatives to traditional monoclonal antibody hybridomatechniques for isolation of monoclonal antibodies.

In some embodiments of the compositions, methods, and uses describedherein, completely human antibodies are used as LAP binding agents,which are particularly desirable for the therapeutic treatment of humanpatients.

Human antibodies can be made by a variety of methods known in the art,including phage display methods described above using antibody librariesderived from human immunoglobulin sequences. See also, U.S. Pat. Nos.4,444,887 and 4,716,111; and PCT publications WO 98/46645, WO 98/50433,WO 98/24893, WO 98/16654, WO 96/34096, WO 96/33735, and WO 91/10741, thecontents of which are herein incorporated by reference in theirentireties.

Human antibodies can also be produced using transgenic mice whichexpress human immunoglobulin genes, and upon immunization are capable ofproducing a full repertoire of human antibodies in the absence ofendogenous immunoglobulin production. For an overview of this technologyfor producing human antibodies, see, Lonberg and Huszar, 1995, Int. Rev.Immunol. 13:65-93. For a detailed discussion of this technology forproducing human antibodies and human monoclonal antibodies and protocolsfor producing such antibodies, see, e.g., PCT publications WO 98/24893;WO 92/01047; WO 96/34096; WO 96/33735; European Patent No. 0 598 877;U.S. Pat. Nos. 5,413,923; 5,625,126; 5,633,425; 5,569,825; 5,661,016;5,545,806; 5,814,318; 5,885,793; 5,916,771; and 5,939,598, the contentsof which are herein incorporated by reference in their entireties. Inaddition, companies such as Abgenix, Inc. (Freemont, Calif.) and Medarex(Princeton, N.J.) can be engaged to provide human antibodies directedagainst a selected antigen using technology similar to that describedabove. See also, e.g., Jakobovits et al., Proc. Natl. Acad. Sci. USA,90:2551 (1993); Jakobovits et al., Nature, 362:255-258 (1993);Bruggermann et al., Year in Immuno., 7:33 (1993); and Duchosal et al.Nature 355:258 (1992), the contents of which are herein incorporated byreference in their entireties. Alternatively, phage display technology(McCafferty et al., Nature 348:552-553 (1990)) can be used to producehuman antibodies and antibody fragments in vitro, from immunoglobulinvariable (V) domain gene repertoires from unimmunized donors. Humanantibodies can also be generated by in vitro activated B cells (see U.S.Pat. Nos. 5,567,610 and 5,229,275, the contents of which are hereinincorporated by reference in their entireties). Completely humanantibodies which recognize a selected epitope can be generated using atechnique referred to as “guided selection.” In this approach a selectednon-human monoclonal antibody, e.g., a mouse antibody, is used to guidethe selection of a completely human antibody recognizing the sameepitope (Jespers et al., 1994, Bio/technology 12:899-903).

“An “Fv” fragment is an antibody fragment which contains a completeantigen recognition and binding site. This region consists of a dimer ofone heavy and one light chain variable domain in tight association,which can be covalent in nature, for example in scFv. It is in thisconfiguration that the three CDRs of each variable domain interact todefine an antigen binding site on the surface of the V_(H)-V_(L) dimer.Collectively, the six CDRs or a subset thereof confer antigen bindingspecificity to the antibody. However, even a single variable domain (orhalf of an Fv comprising only three CDRs specific for an antigen) hasthe ability to recognize and bind antigen, although usually at a loweraffinity than the entire binding site.

“Framework regions” (hereinafter FR) are those variable domain residuesother than the CDR residues. Each variable domain typically has four FRsidentified as FR1, FR2, FR3 and FR4. If the CDRs are defined accordingto Kabat, the light chain FR residues are positioned at about residues1-23 (LCFR1), 35-49 (LCFR2), 57-88 (LCFR3), and 98-107 (LCFR4) and theheavy chain FR residues are positioned about at residues 1-30 (HCFR1),36-49 (HCFR2), 66-94 (HCFR3), and 103-113 (HCFR4) in the heavy chainresidues. If the CDRs comprise amino acid residues from hypervariableloops, the light chain FR residues are positioned about at residues 1-25(LCFR1), 33-49 (LCFR2), 53-90 (LCFR3), and 97-107 (LCFR4) in the lightchain and the heavy chain FR residues are positioned about at residues1-25 (HCFR1), 33-52 (HCFR2), 56-95 (HCFR3), and 102-113 (HCFR4) in theheavy chain residues. In some instances, when the CDR comprises aminoacids from both a CDR as defined by Kabat and those of a hypervariableloop, the FR residues will be adjusted accordingly. For example, whenCDRH1 includes amino acids H26-H35, the heavy chain FR1 residues are atpositions 1-25 and the FR2 residues are at positions 36-49. Eachcomplementarity determining region may comprise amino acid residues froma “complementarity determining region” as defined by Kabat (i.e. aboutresidues 24-34 (L1), 50-56 (L2) and 89-97 (L3) in the light chainvariable domain and 31-35 (H1), 50-65 (H2) and 95-102 (H3) in the heavychain variable domain; Kabat et al., Sequences of Proteins ofImmunological Interest, 5th Ed. Public Health Service, NationalInstitutes of Health, Bethesda, Md. (1991)) and/or those residues from a“hypervariable loop” (i.e. about residues 26-32 (L1), 50-52 (L2) and91-96 (L3) in the light chain variable domain and 26-32 (H1), 53-55 (H2)and 96-101 (H3) in the heavy chain variable domain; Chothia and Lesk J.Mol. Biol. 196:901-917 (1987)). In some instances, a complementaritydetermining region can include amino acids from both a CDR regiondefined according to Kabat and a hypervariable loop.

“Humanized antibodies,” as the term is used herein, refer to antibodymolecules from a non-human species, where the antibodies that bind thedesired antigen, i.e., LAP or LAP bound to a ligand, have one or moreCDRs from the non-human species, and framework and constant regions froma human immunoglobulin molecule. Often, framework residues in the humanframework regions will be substituted with the corresponding residuefrom the CDR donor antibody to alter, preferably improve, antigenbinding. These framework substitutions are identified by methods wellknown in the art, e.g., by modeling of the interactions of the CDR andframework residues to identify framework residues important for antigenbinding and sequence comparison to identify unusual framework residuesat particular positions. (See, e.g., Queen et al., U.S. Pat. No.5,585,089; Riechmann et al., 1988, Nature 332:323. Antibodies can behumanized using a variety of techniques known in the art including, forexample, CDR-grafting (EP 239,400; PCT publication WO 91/09967; U.S.Pat. Nos. 5,225,539; 5,530,101; and 5,585,089), veneering or resurfacing(EP 592,106; EP 519,596; Padlan, Molecular Immunology, 1991,28(4/5):489-498; Studnicka et al., 1994, Protein Engineering7(6):805-814; Roguska. et al, 1994, PNAS 91:969-973), and chainshuffling (U.S. Pat. No. 5,565,332), the contents of which are hereinincorporated by reference in their entireties. Accordingly, a humanizedantibody has one or more amino acid residues introduced into it from asource which is non-human. These non-human amino acid residues are oftenreferred to as “import” residues, which are typically taken from an“import” variable domain. Humanization can be essentially performedfollowing the method of Winter and co-workers (Jones et al., Nature,321:522-525 (1986); Riechmann et al., Nature, 332:323-327 (1988);Verhoeyen et al., Science, 239:1534-1536 (1988)), the contents of whichare herein incorporated by reference in their entireties, bysubstituting rodent CDRs or CDR sequences for the correspondingsequences of a human antibody. Accordingly, such “humanized” antibodiesare chimeric antibodies (U.S. Pat. No. 4,816,567, the contents of whichare herein incorporated by reference in its entirety) whereinsubstantially less than an intact human variable domain has beensubstituted by the corresponding sequence from a non-human species. Inpractice, humanized antibodies are typically human antibodies in whichsome CDR residues and possibly some FR residues are substituted byresidues from analogous sites in rodent antibodies.

The “Fab” fragment contains a variable and constant domain of the lightchain and a variable domain and the first constant domain (C_(H)1) ofthe heavy chain. F(ab′)₂ antibody fragments comprise a pair of Fabfragments which are generally covalently linked near their carboxytermini by hinge cysteines between them. Other chemical couplings ofantibody fragments are also known in the art.

“Single-chain Fv” or “scFv” antibody fragments comprise the V_(H) andV_(L) domains of antibody, wherein these domains are present in a singlepolypeptide chain. Generally the Fv polypeptide further comprises apolypeptide linker between the V_(H) and V_(L) domains, which enablesthe scFv to form the desired structure for antigen binding. For a reviewof scFv, see Pluckthun in The Pharmacology of Monoclonal Antibodies, Vol113, Rosenburg and Moore eds. Springer-Verlag, New York, pp. 269-315(1994).

The term “diabodies” refers to small antibody fragments with twoantigen-binding sites, which fragments comprise a heavy chain variabledomain (V_(H)) connected to a light chain variable domain (V_(L)) in thesame polypeptide chain (V_(H) and V_(L)). By using a linker that is tooshort to allow pairing between the two domains on the same chain, thedomains are forced to pair with the complementary domains of anotherchain and create two antigen-binding sites. Diabodies are described morefully in, for example, EP 404,097; WO 93/11161; and Hollinger et al.,Proc. Natl. Acad. Sci. USA, 90:6444-6448 (1993).

The expression “linear antibodies” refers to the antibodies described inZapata et al., Protein Eng., 8(10):1057-1062 (1995). Briefly, theseantibodies comprise a pair of tandem Fd segments(V_(H)-C_(H)1-V_(H)-C_(H)1) which, together with complementary lightchain polypeptides, form a pair of antigen binding regions. Linearantibodies can be bispecific or monospecific.

Various techniques have been developed for the production of antibody orantigen-binding fragments. The antibodies described herein can befragmented using conventional techniques and the fragments screened forutility in the same manner as described above for the whole antibodies.Traditionally, these fragments were derived via proteolytic digestion ofintact antibodies (see, e.g., Morimoto et al., Journal of Biochemicaland Biophysical Methods 24:107-117 (1992) and Brennan et al., Science,229:81 (1985)). For example, Fab and F(ab′)₂ fragments of the bispecificand multispecific antibodies described herein can be produced byproteolytic cleavage of immunoglobulin molecules, using enzymes such aspapain (to produce Fab fragments) or pepsin (to produce F(ab′) 2fragments). F(ab′) 2 fragments contain the variable region, the lightchain constant region and the C_(H)1 domain of the heavy chain. However,these fragments can now be produced directly by recombinant host cells.For example, the antibody fragments can be isolated from the antibodyphage libraries discussed above. Alternatively, Fab′-SH fragments can bedirectly recovered from E. coli and chemically coupled to form F(ab′)₂fragments (Carter et al., Bio/Technology 10:163-167 (1992)). Accordingto another approach, F(ab′)₂ fragments can be isolated directly fromrecombinant host cell culture. Other techniques for the production ofantibody fragments will be apparent to the skilled practitioner. Inother embodiments, the antibody of choice is a single chain Fv fragment(scFv). See WO 93/16185.

Examples of techniques which can be used to produce single-chain Fvs andantibodies include those described in U.S. Pat. Nos. 4,946,778 and5,258,498; Huston et al., 1991, Methods in Enzymology 203:46-88; Shu etal., 1993, PNAS 90:7995-7999; and Skerra et al., 1988, Science240:1038-1040. For some uses, including the in vivo use of antibodies inhumans as described herein and in vitro proliferation or cytotoxicityassays, it is preferable to use chimeric, humanized, or humanantibodies.

An “affinity matured” antibody is one with one or more alterations inone or more CDRs thereof which result an improvement in the affinity ofthe antibody for antigen, compared to a parent antibody which does notpossess those alteration(s). Preferred affinity matured antibodies willhave nanomolar or even picomolar affinities for the target antigen.Affinity matured antibodies are produced by procedures known in the art.Marks et al. Bio/Technology 10:779-783 (1992) describes affinitymaturation by V_(H) and V_(L) domain shuffling. Random mutagenesis ofCDR and/or framework residues is described by: Barbas et al. Proc Nat.Acad. Sci, USA 91:3809-3813 (1994); Schier et al. Gene 169:147-155(1995); Yelton et al. J. Immunol. 155:1994-2004 (1995); Jackson et al.,J. Immunol. 154(7):3310-9 (1995); and Hawkins et al., J. Mol. Biol.226:889-896 (1992).

As used herein “complementary” refers to when two immunoglobulin domainsbelong to families of structures which form cognate pairs or groups orare derived from such families and retain this feature. For example, aV_(H) domain and a V_(L) domain of a natural antibody are complementary;two V_(H) domains are not complementary, and two V_(L) domains are notcomplementary. Complementary domains can be found in other members ofthe immunoglobulin superfamily, such as the V_(α) and V_(β) (or γ and δ)domains of the T-cell receptor. Domains which are artificial, such asdomains based on protein scaffolds which do not bind epitopes unlessengineered to do so, are non-complementary. Likewise, two domains basedon, for example, an immunoglobulin domain and a fibronectin domain arenot complementary.

In some embodiments of the compositions, methods, and uses describedherein, the LAP binding agent is a small molecule inhibitor, agent, orcompound.

In some embodiments of the methods described herein, a LAP smallmolecule binding agent for use in the methods described herein can bindor physically interact with a LAP ligand interaction site, e.g. a sitethat interacts with mature TGF-β, a site that interacts with integrins,and/or a site that interacts with LTBP.

In some embodiments of the methods described herein, a LAP smallmolecule binding agent binds or physically interacts with R189 of SEQ IDNOs: 1 and 4, R196 of SEQ ID NOs: 2 and 5, and/or R192 of SEQ ID NOs: 3and 6. In some embodiments of the methods described herein, a LAP smallmolecule binding agent binds or physically interacts with amino acids215-217 of SEQ ID NOs: 1 and 4, amino acids 241-243 of SEQ ID NOs: 2 and5, and/or amino acids 238-240 of SEQ ID NOs: 3 and 6. In someembodiments of the methods described herein, a LAP small moleculebinding agent binds or physically interacts with Cys4 of any of SEQ IDNOs: 1-6.

In some embodiments of the methods described herein, a LAP smallmolecule binding agent for use in the methods described herein can bindor physically interact with a LAP homodimerization site, i.e., a sitethat interacts with another LAP molecule. Accordingly, in someembodiments of the methods described herein, a LAP small moleculebinding agent binds or physically interacts with Cys194 and/or Cys196 ofSEQ ID NOs: 1 and 4, Cys206 and/or Cys208 of SEQ ID NOs: 2 and 5, and/orCys204 and/or Cys206 of SEQ ID NOs: 3 and 6.

Such small molecule inhibitors include, but are not limited to, smallpeptides or peptide-like molecules, soluble peptides, and syntheticnon-peptidyl organic or inorganic compounds. A small molecule inhibitoror antagonist can have a molecular weight of any of about 100 to about20,000 daltons (Da), about 500 to about 15,000 Da, about 1000 to about10,000 Da.

In some embodiments of the compositions, methods, and uses describedherein, a LAP binding agent is an RNA or DNA aptamer that binds orphysically interacts with LAP, and modulates interactions between LAPand any of its ligands.

In some embodiments of the methods described herein, a LAP RNA or DNAaptamer for use in the methods described herein can bind a LAP ligandinteraction site, e.g. a site that interacts with mature TGFβ, a sitethat interacts with integrins, and/or a site that interacts with LTBP.

In some embodiments of the methods described herein, a LAP RNA or DNAaptamer binds R189 of SEQ ID NOs: 1 and 4, R196 of SEQ ID NOs: 2 and 5,and/or R192 of SEQ ID NOs: 3 and 6. In some embodiments of the methodsdescribed herein, a LAP RNA or DNA aptamer binds or physically interactswith amino acids 215-217 of SEQ ID NOs: 1 and 4, amino acids 241-243 ofSEQ ID NOs: 2 and 5, and/or amino acids 238-240 of SEQ ID NOs: 3 and 6.In some embodiments of the methods described herein, a RNA or DNAaptamer binds or physically interacts with Cys4 of any of SEQ ID NOs:1-6.

In some embodiments of the methods described herein, a LAP RNA or DNAaptamer for use in the methods described herein can bind or physicallyinteract with a LAP homodimerization site, i.e., a site that interactswith another LAP molecule. Accordingly, in some embodiments of themethods described herein, a LAP RNA or DNA aptamer binds or physicallyinteracts with Cys194 and/or Cys196 of SEQ ID NOs: 1 and 4, Cys206and/or Cys208 of SEQ ID NOs: 2 and 5, and/or Cys204 and/or Cys206 of SEQID NOs: 3 and 6.

LAP binding agents for use in the compositions and methods describedherein can be identified or characterized using methods known in theart, such as protein-protein binding assays, biochemical screeningassays, immunoassays, and cell-based assays, which are well known in theart, including, but not limited to, those described herein in theExamples and Figures.

For the clinical use of the methods and uses described herein,administration of the compositions comprising LAP-binding agents caninclude formulation into pharmaceutical compositions or pharmaceuticalformulations for parenteral administration, e.g., intravenous; mucosal,e.g., intranasal; ocular, or other mode of administration. In someembodiments, the LAP binding agents described herein, can beadministered along with any pharmaceutically acceptable carriercompound, material, or composition which results in an effectivetreatment in the subject. Thus, a pharmaceutical formulation for use inthe methods described herein can contain LAP binding agents as describedherein in combination with one or more pharmaceutically acceptableingredients.

The phrase “pharmaceutically acceptable” refers to those compounds,materials, compositions, and/or dosage forms which are, within the scopeof sound medical judgment, suitable for use in contact with the tissuesof human beings and animals without excessive toxicity, irritation,allergic response, or other problem or complication, commensurate with areasonable benefit/risk ratio. The phrase “pharmaceutically acceptablecarrier” as used herein means a pharmaceutically acceptable material,composition or vehicle, such as a liquid or solid filler, diluent,excipient, solvent, media, encapsulating material, manufacturing aid(e.g., lubricant, talc magnesium, calcium or zinc stearate, or stericacid), or solvent encapsulating material, involved in maintaining thestability, solubility, or activity of a LAP binding agent. Each carriermust be “acceptable” in the sense of being compatible with the otheringredients of the formulation and not injurious to the patient. Someexamples of materials which can serve as pharmaceutically-acceptablecarriers include: (1) sugars, such as lactose, glucose and sucrose; (2)starches, such as corn starch and potato starch; (3) cellulose, and itsderivatives, such as sodium carboxymethyl cellulose, methylcellulose,ethyl cellulose, microcrystalline cellulose and cellulose acetate; (4)powdered tragacanth; (5) malt; (6) gelatin; (7) excipients, such ascocoa butter and suppository waxes; (8) oils, such as peanut oil,cottonseed oil, safflower oil, sesame oil, olive oil, corn oil andsoybean oil; (9) glycols, such as propylene glycol; (10) polyols, suchas glycerin, sorbitol, mannitol and polyethylene glycol (PEG); (11)esters, such as ethyl oleate and ethyl laurate; (12) agar; (13)buffering agents, such as magnesium hydroxide and aluminum hydroxide;(14) alginic acid; (15) pyrogen-free water; (16) isotonic saline; (17)Ringer's solution; (19) pH buffered solutions; (20) polyesters,polycarbonates and/or polyanhydrides; (21) bulking agents, such aspolypeptides and amino acids (22) serum components, such as serumalbumin, HDL and LDL; (23) C2-C12 alchols, such as ethanol; and (24)other non-toxic compatible substances employed in pharmaceuticalformulations. Release agents, coating agents, preservatives, andantioxidants can also be present in the formulation. The terms such as“excipient”, “carrier”, “pharmaceutically acceptable carrier” or thelike are used interchangeably herein.

The LAP binding agents described herein can be specially formulated foradministration of the compound to a subject in solid, liquid or gelform, including those adapted for the following: (1) parenteraladministration, for example, by subcutaneous, intramuscular, intravenousor epidural injection as, for example, a sterile solution or suspension,or sustained-release formulation; (2) topical application, for example,as a cream, ointment, or a controlled-release patch or spray applied tothe skin; (3) intravaginally or intrarectally, for example, as apessary, cream or foam; (4) ocularly; (5) transdermally; (6)transmucosally; or (79) nasally. Additionally, a LAP-binding agent canbe implanted into a patient or injected using a drug delivery system.See, for example, Urquhart, et al., Ann. Rev. Pharmacol. Toxicol. 24:199-236 (1984); Lewis, ed. “Controlled Release of Pesticides andPharmaceuticals” (Plenum Press, New York, 1981); U.S. Pat. No.3,773,919; and U.S. Pat. No. 35 3,270,960.

Further embodiments of the formulations and modes of administration ofthe compositions comprising LAP binding agents that can be used in themethods described herein are described below.

Parenteral Dosage Forms. Parenteral dosage forms of the LAP bindingagents can also be administered to a subject by various routes,including, but not limited to, subcutaneous, intravenous (includingbolus injection), intramuscular, and intraarterial. Since administrationof parenteral dosage forms typically bypasses the patient's naturaldefenses against contaminants, parenteral dosage forms are preferablysterile or capable of being sterilized prior to administration to apatient. Examples of parenteral dosage forms include, but are notlimited to, solutions ready for injection, dry products ready to bedissolved or suspended in a pharmaceutically acceptable vehicle forinjection, suspensions ready for injection, controlled-releaseparenteral dosage forms, and emulsions.

Suitable vehicles that can be used to provide parenteral dosage forms ofthe disclosure are well known to those skilled in the art. Examplesinclude, without limitation: sterile water; water for injection USP;saline solution; glucose solution; aqueous vehicles such as but notlimited to, sodium chloride injection, Ringer's injection, dextroseInjection, dextrose and sodium chloride injection, and lactated Ringer'sinjection; water-miscible vehicles such as, but not limited to, ethylalcohol, polyethylene glycol, and propylene glycol; and non-aqueousvehicles such as, but not limited to, corn oil, cottonseed oil, peanutoil, sesame oil, ethyl oleate, isopropyl myristate, and benzyl benzoate.

Aerosol formulations. The LAP binding agents can be packaged in apressurized aerosol container together with suitable propellants, forexample, hydrocarbon propellants like propane, butane, or isobutane withconventional adjuvants. A LAP binding agent described herein, can alsobe administered in a non-pressurized form such as in a nebulizer oratomizer. The LAP binding agents described herein, can also beadministered directly to the airways in the form of a dry powder, forexample, by use of an inhaler.

Suitable powder compositions include, by way of illustration, powderedpreparations of the LAP binding agents described herein, thoroughlyintermixed with lactose, or other inert powders acceptable forintrabronchial administration. The powder compositions can beadministered via an aerosol dispenser or encased in a breakable capsulewhich can be inserted by the subject into a device that punctures thecapsule and blows the powder out in a steady stream suitable forinhalation. The compositions can include propellants, surfactants, andco-solvents and can be filled into conventional aerosol containers thatare closed by a suitable metering valve.

Aerosols for the delivery to the respiratory tract are known in the art.See for example, Adjei, A. and Garren, J. Pharm. Res., 1: 565-569(1990); Zanen, P. and Lamm, J.-W. J. Int. J. Pharm., 114: 111-115(1995); Gonda, I. “Aerosols for delivery of therapeutic and diagnosticagents to the respiratory tract,” in Critical Reviews in TherapeuticDrug Carrier Systems, 6:273-313 (1990); Anderson et al., Am. Rev.Respir. Dis., 140: 1317-1324 (1989)) and have potential for the systemicdelivery of peptides and proteins as well (Patton and Platz, AdvancedDrug Delivery Reviews, 8:179-196 (1992)); Timsina et. al., Int. J.Pharm., 101: 1-13 (1995); and Tansey, I. P., Spray Technol. Market,4:26-29 (1994); French, D. L., Edwards, D. A. and Niven, R. W., AerosolSci., 27: 769-783 (1996); Visser, J., Powder Technology 58: 1-10(1989)); Rudt, S. and R. H. Muller, J. Controlled Release, 22: 263-272(1992); Tabata, Y, and Y. Ikada, Biomed. Mater. Res., 22: 837-858(1988); Wall, D. A., Drug Delivery, 2: 10 1-20 1995); Patton, J. andPlatz, R., Adv. Drug Del. Rev., 8: 179-196 (1992); Bryon, P., Adv. Drug.Del. Rev., 5: 107-132 (1990); Patton, J. S., et al., Controlled Release,28: 15 79-85 (1994); Damms, B. and Bains, W., Nature Biotechnology(1996); Niven, R. W., et al., Pharm. Res., 12(9); 1343-1349 (1995); andKobayashi, S., et al., Pharm. Res., 13(1): 80-83 (1996), contents of allof which are herein incorporated by reference in their entirety.

The formulations of the LAP binding agents described herein, furtherencompass anhydrous pharmaceutical compositions and dosage formscomprising the disclosed compounds as active ingredients, since watercan facilitate the degradation of some compounds. For example, theaddition of water (e.g., 5%) is widely accepted in the pharmaceuticalarts as a means of simulating long-term storage in order to determinecharacteristics such as shelf life or the stability of formulations overtime. See, e.g., Jens T. Carstensen, Drug Stability: Principles &Practice, 379-80 (2nd ed., Marcel Dekker, NY, N.Y.: 1995). Anhydrouspharmaceutical compositions and dosage forms of the disclosure can beprepared using anhydrous or low moisture containing ingredients and lowmoisture or low humidity conditions. Pharmaceutical compositions anddosage forms that comprise lactose and at least one active ingredientthat comprises a primary or secondary amine are preferably anhydrous ifsubstantial contact with moisture and/or humidity during manufacturing,packaging, and/or storage is expected. Anhydrous compositions arepreferably packaged using materials known to prevent exposure to watersuch that they can be included in suitable formulary kits. Examples ofsuitable packaging include, but are not limited to, hermetically sealedfoils, plastics, unit dose containers (e.g., vials) with or withoutdesiccants, blister packs, and strip packs.

Controlled and Delayed Release Dosage Forms. In some embodiments of theaspects described herein, the LAP binding agents can be administered toa subject by controlled- or delayed-release means. Ideally, the use ofan optimally designed controlled-release preparation in medicaltreatment is characterized by a minimum of drug substance being employedto cure or control the condition in a minimum amount of time. Advantagesof controlled-release formulations include: 1) extended activity of thedrug; 2) reduced dosage frequency; 3) increased patient compliance; 4)usage of less total drug; 5) reduction in local or systemic sideeffects; 6) minimization of drug accumulation; 7) reduction in bloodlevel fluctuations; 8) improvement in efficacy of treatment; 9)reduction of potentiation or loss of drug activity; and 10) improvementin speed of control of diseases or conditions. (Kim, Cherng-ju,Controlled Release Dosage Form Design, 2 (Technomic Publishing,Lancaster, Pa.: 2000)). Controlled-release formulations can be used tocontrol a compound of formula (I)'s onset of action, duration of action,plasma levels within the therapeutic window, and peak blood levels. Inparticular, controlled- or extended-release dosage forms or formulationscan be used to ensure that the maximum effectiveness of a compound offormula (I) is achieved while minimizing potential adverse effects andsafety concerns, which can occur both from under-dosing a drug (i.e.,going below the minimum therapeutic levels) as well as exceeding thetoxicity level for the drug.

A variety of known controlled- or extended-release dosage forms,formulations, and devices can be adapted for use with the LAP bindingagents described herein. Examples include, but are not limited to, thosedescribed in U.S. Pat. Nos. 3,845,770; 3,916,899; 3,536,809; 3,598,123;4,008,719; 5,674,533; 5,059,595; 5,591,767; 5,120,548; 5,073,543;5,639,476; 5,354,556; 5,733,566; and 6,365,185 B1, each of which isincorporated herein by reference in their entireties. These dosage formscan be used to provide slow or controlled-release of one or more activeingredients using, for example, hydroxypropylmethyl cellulose, otherpolymer matrices, gels, permeable membranes, osmotic systems (such asOROS® (Alza Corporation, Mountain View, Calif. USA)), multilayercoatings, microparticles, liposomes, or microspheres or a combinationthereof to provide the desired release profile in varying proportions.Additionally, ion exchange materials can be used to prepare immobilized,adsorbed salt forms of the disclosed compounds and thus effectcontrolled delivery of the drug. Examples of specific anion exchangersinclude, but are not limited to, DUOLITE® A568 and DUOLITE® AP143 (Rohm& Haas, Spring House, Pa. USA).

In some embodiments of the methods described herein, the LAP bindingagents for use in the methods described herein are administered to asubject by sustained release or in pulses. Pulse therapy is not a formof discontinuous administration of the same amount of a composition overtime, but comprises administration of the same dose of the compositionat a reduced frequency or administration of reduced doses. Sustainedrelease or pulse administrations are particularly preferred when thedisorder occurs continuously in the subject, for example where thesubject has continuous or chronic symptoms of a viral infection. Eachpulse dose can be reduced and the total amount of the LAP binding agentsdescribed herein administered over the course of treatment to thesubject or patient is minimized.

The interval between pulses, when necessary, can be determined by one ofordinary skill in the art. Often, the interval between pulses can becalculated by administering another dose of the composition when thecomposition or the active component of the composition is no longerdetectable in the subject prior to delivery of the next pulse. Intervalscan also be calculated from the in vivo half-life of the composition.Intervals can be calculated as greater than the in vivo half-life, or 2,3, 4, 5 and even 10 times greater the composition half-life. Variousmethods and apparatus for pulsing compositions by infusion or otherforms of delivery to the patient are disclosed in U.S. Pat. Nos.4,747,825; 4,723,958; 4,948,592; 4,965,251 and 5,403,590.

Methods of Treatment and Uses of LAP Binding Agents

As demonstrated herein, intracranial and subcutaneous GBM tumor growthis lower and mice survive longer when treated with anti-LAP antibodies.Anti-LAP antibody treatment also affected both systemic and intra-tumorimmunity as follows: (1) Tumors were infiltrated by increased numbers ofcytotoxic CD8+ T cells and intra-tumor Foxp3 Tregs were decreased. CD4+and CD8+ intra-tumor T cells had decreased expression of PD-1, LAG3 andCD103. (2) In the periphery, CD4+ and CD8+ T cells, expressing IFN-γ andgranzyme B, were increased, respectively whereas CD103+ T cells weredecreased. Finally, there were reduced numbers of tolerogenic dendriticcells expressing CD103 and PD-L1 whereas MHC II was elevated on splenicmyeloid cells. Anti-LAP antibodies were also tested in a melanoma modeland colorectal cancer model and similar intra-tumor and peripheralimmune effects were observed. Thus, as demonstrated herein, inhibitionof LAP strongly influences systemic and intra-tumor immune responses byactivating both innate and adaptive immunity and overcomes themechanisms suppressing tumor-specific immunity. In conclusion, LAPbinding agents as monotherapies or combined with conventional anti-tumormodalities represent novel immunotherapeutic approaches for thetreatment of various cancers, including, but not limited to, braintumors, melanoma, and colorectal cancer.

Provided herein, in some aspects, are methods to treat cancer and tumorswhere LAP expression and/or activity is associated with suppression ofcancer- or tumor-specific immunity comprising administering atherapeutically effective amount of a LAP binding agenty agent to asubject in need thereof.

In some aspects, provided herein are methods to increase tumor-specificimmunity comprising administering a therapeutically effective amount ofa LAP binding agenty agent to a subject in need thereof.

In some embodiments of these aspects and all such aspects describedherein, the subject has or has been diagnosed with cancer.

A “cancer” or “tumor” as used herein refers to an uncontrolled growth ofcells which interferes with the normal functioning of the bodily organsand systems. A subject that has a cancer or a tumor is a subject havingobjectively measurable cancer cells present in the subject's body.Included in this definition are benign and malignant cancers, as well asdormant tumors or micrometastases. Cancers which migrate from theiroriginal location and seed vital organs can eventually lead to the deathof the subject through the functional deterioration of the affectedorgans. Hemopoietic cancers, such as leukemia, are able to out-competethe normal hemopoietic compartments in a subject, thereby leading tohemopoietic failure (in the form of anemia, thrombocytopenia andneutropenia) ultimately causing death.

By “metastasis” is meant the spread of cancer from its primary site toother places in the body. Cancer cells can break away from a primarytumor, penetrate into lymphatic and blood vessels, circulate through thebloodstream, and grow in a distant focus (metastasize) in normal tissueselsewhere in the body. Metastasis can be local or distant. Metastasis isa sequential process, contingent on tumor cells breaking off from theprimary tumor, traveling through the bloodstream, and stopping at adistant site. At the new site, the cells establish a blood supply andcan grow to form a life-threatening mass. Both stimulatory andinhibitory molecular pathways within the tumor cell regulate thisbehavior, and interactions between the tumor cell and host cells in thedistant site are also significant.

Metastases are most often detected through the sole or combined use ofmagnetic resonance imaging (MRI) scans, computed tomography (CT) scans,blood and platelet counts, liver function studies, chest X-rays and bonescans in addition to the monitoring of specific symptoms.

Examples of cancer include but are not limited to, carcinoma, lymphoma,blastoma, sarcoma, and leukemia. More particular examples of suchcancers include, but are not limited to, basal cell carcinoma, biliarytract cancer; bladder cancer; bone cancer; brain and CNS cancer; breastcancer; cancer of the peritoneum; cervical cancer; cholangiocarcinoma;choriocarcinoma; colon and rectum cancer; connective tissue cancer;cancer of the digestive system; endometrial cancer; esophageal cancer;eye cancer; cancer of the head and neck; gastric cancer (includinggastrointestinal cancer); glioblastoma; hepatic carcinoma; hepatoma;intra-epithelial neoplasm; kidney or renal cancer; larynx cancer;leukemia; liver cancer; lung cancer (e.g., small-cell lung cancer,non-small cell lung cancer, adenocarcinoma of the lung, and squamouscarcinoma of the lung); lymphoma including Hodgkin's and non-Hodgkin'slymphoma; melanoma; myeloma; neuroblastoma; oral cavity cancer (e.g.,lip, tongue, mouth, and pharynx); ovarian cancer; pancreatic cancer;prostate cancer; retinoblastoma; rhabdomyosarcoma; rectal cancer; cancerof the respiratory system; salivary gland carcinoma; sarcoma; skincancer; squamous cell cancer; stomach cancer; teratocarcinoma;testicular cancer; thyroid cancer; uterine or endometrial cancer; cancerof the urinary system; vulval cancer; as well as other carcinomas andsarcomas; as well as B-cell lymphoma (including low grade/follicularnon-Hodgkin's lymphoma (NHL); small lymphocytic (SL) NHL; intermediategrade/follicular NHL; intermediate grade diffuse NHL; high gradeimmunoblastic NHL; high grade lymphoblastic NHL; high grade smallnon-cleaved cell NHL; bulky disease NHL; mantle cell lymphoma;AIDS-related lymphoma; and Waldenstrom's Macroglobulinemia); chroniclymphocytic leukemia (CLL); acute lymphoblastic leukemia (ALL); Hairycell leukemia; chronic myeloblastic leukemia; and post-transplantlymphoproliferative disorder (PTLD), as well as abnormal vascularproliferation associated with phakomatoses, edema (such as thatassociated with brain tumors), tumors of primitive origins and Meigs'syndrome.

In some embodiments of these methods and all such methods describedherein, the subject in need thereof has or has been diagnosed with abrain tumor. In some such embodiments, the brain tumor is glioblastoma.

In some embodiments of these methods and all such methods describedherein, the subject in need thereof has or has been diagnosed withmelanoma.

In some embodiments of these methods and all such methods describedherein, the subject in need thereof has or has been diagnosed with acolorectal cancer.

In some embodiments of these methods and all such methods describedherein, the subject in need thereof has or has been diagnosed with abrain tumor, a melanoma, or colorectal cancer. In some such embodiments,the brain tumor is glioblastoma.

In some embodiments of these methods and all such methods describedherein, the methods further comprise administering an anti-cancertherapy or agent to a subject in addition to the LAP binding agent(s)described herein.

The term “anti-cancer therapy” refers to a therapy useful in treatingcancer. Examples of anti-cancer therapeutic agents include, but are notlimited to, e.g., surgery, chemotherapeutic agents, growth inhibitoryagents, cytotoxic agents, radiotherapy and agents used in radiationtherapy, anti-angiogenesis agents, apoptotic agents, anti-tubulinagents, and other agents to treat cancer, such as anti-HER-2 antibodies(e.g., HERCEPTIN®), anti-CD20 antibodies, an epidermal growth factorreceptor (EGFR) antagonist (e.g., a tyrosine kinase inhibitor),HER1/EGFR inhibitor (e.g., erlotinib (TARCEVA®)), platelet derivedgrowth factor inhibitors (e.g., GLEEVEC™ (Imatinib Mesylate)), a COX-2inhibitor (e.g., celecoxib), interferons, cytokines, antagonists (e.g.,neutralizing antibodies) that bind to one or more of the followingtargets PD1, PDL1, PDL2 (e.g., pembrolizumab; nivolumab; MK-3475;AMP-224; MPDL3280A; MEDI0680; MSB0010718C; and/or MEDI4736); CTLA4(e.g., tremelimumab (PFIZER) and ipilimumab); LAG3 (e.g., BMS-986016);CD103; TIM-3 and/or other TIM family members; CEACAM-1 and/or otherCEACAM family members, ErbB2, ErbB3, ErbB4, PDGFR-beta, BlyS, APRIL,BCMA or VEGF receptor(s), TRAIL/Apo2, and other bioactive and organicchemical agents, etc. Combinations thereof are also specificallycontemplated for the methods described herein.

In some embodiments of the methods described herein, an anti-cancertherapy to be administered with the LAP binding agents described hereincomprises a PD1, PDL1, and/or PDL2 inhibitory agent, such as anantibody. Non-limiting examples of such PD1, PDL1, and PDL2 inhibitoryagents include pembrolizumab (KEYTRUDA, MERCK); nivolumab (BRISTOL-MYERSSQUIBB); MK-3475; MPDL3280A (GENENTECH); MEDI0680 and MEDI4736(MEDIMMUNE/ASTRAZENECA); AMP-224; and MSB0010718C. Additionalnon-limiting examples of anti-PD1 antibody reagents can include PD1binding site sequences from monoclonal antibodies specific for humanPD1, such as, MDX-1106 (ONO-4538), a fully human IgG4 anti-PD1 blockingantibody (Journal of Clinical Oncology, 2008 Vol 26, No 15S); CT-011(CureTech, LTD, previously CT-AcTibody or BAT), a humanized monoclonalIgG1 antibody (Benson D M et al, Blood. 2010 May 11), or those obtainedfrom, clone NAT (Abeam), clone EH12.2H7 (Biolegend), clone J1 16(eBioscience), clone MIH4 (eBioscience), clone J105 (eBioscience), orclone 192106 (R& D systems).

In some embodiments, an anti-cancer therapy comprises an immunotherapysuch as adoptive cell transfer. “Adoptive cell transfer,” as usedherein, refers to immunotherapies involving genetically engineering asubject or patient's own T cells to produce special receptors on theirsurface called chimeric antigen receptors (CARs). CARs are proteins thatallow the T cells to recognize a specific protein (antigen) on tumorcells. These engineered CAR T cells are then grown in the laboratoryuntil they number in the billions. The expanded population of CAR Tcells is then infused into the patient. After the infusion, the T cellsmultiply in the subject's body and, with guidance from their engineeredreceptor, recognize and kill cancer cells that harbor the antigen ontheir surfaces.

The term “cytotoxic agent” as used herein refers to a substance thatinhibits or prevents the function of cells and/or causes destruction ofcells. The term is intended to include radioactive isotopes (e.g. At²¹¹,I¹³¹, I¹²⁵, Y⁹⁰, Re¹⁸⁶, Re¹⁸⁸, Sm¹⁵³, Bi²¹², P³² and radioactiveisotopes of Lu), chemotherapeutic agents, and toxins such as smallmolecule toxins or enzymatically active toxins of bacterial, fungal,plant or animal origin, including active fragments and/or variantsthereof.

In some embodiments of these methods and all such methods describedherein, the methods further comprise administering a chemotherapeuticagent, such as, for example, temozolomide, to the subject beingadministered the LAP binding agent(s) described herein.

Non-limiting examples of chemotherapeutic agents can include alkylatingagents such as thiotepa and CYTOXAN® cyclosphosphamide; temozolomide;alkyl sulfonates such as busulfan, improsulfan and piposulfan;aziridines such as benzodopa, carboquone, meturedopa, and uredopa;ethylenimines and methylamelamines including altretamine,triethylenemelamine, trietylenephosphoramide,triethiylenethiophosphoramide and trimethylolomelamine; acetogenins(especially bullatacin and bullatacinone); a camptothecin (including thesynthetic analogue topotecan); bryostatin; callystatin; CC-1065(including its adozelesin, carzelesin and bizelesin syntheticanalogues); cryptophycins (particularly cryptophycin 1 and cryptophycin8); dolastatin; duocarmycin (including the synthetic analogues, KW-2189and CB1-TM1); eleutherobin; pancratistatin; a sarcodictyin;spongistatin; nitrogen mustards such as chlorambucil, chlornaphazine,cholophosphamide, estramustine, ifosfamide, mechlorethamine,mechlorethamine oxide hydrochloride, melphalan, novembichin,phenesterine, prednimustine, trofosfamide, uracil mustard; nitrosureassuch as carmustine, chlorozotocin, fotemustine, lomustine, nimustine,and ranimnustine; antibiotics such as the enediyne antibiotics (e.g.,calicheamicin, especially calicheamicin gamma1I and calicheamicinomegaI1 (see, e.g., Agnew, Chem. Intl. Ed. Engl., 33: 183-186 (1994));dynemicin, including dynemicin A; bisphosphonates, such as clodronate;an esperamicin; as well as neocarzinostatin chromophore and relatedchromoprotein enediyne antiobiotic chromophores), aclacinomysins,actinomycin, authramycin, azaserine, bleomycins, cactinomycin,carabicin, caminomycin, carzinophilin, chromomycinis, dactinomycin,daunorubicin, detorubicin, 6-diazo-5-oxo-L-norleucine, ADRIAMYCIN®doxorubicin (including morpholino-doxorubicin,cyanomorpholino-doxorubicin, 2-pyrrolino-doxorubicin anddeoxydoxorubicin), epirubicin, esorubicin, idarubicin, marcellomycin,mitomycins such as mitomycin C, mycophenolic acid, nogalamycin,olivomycins, peplomycin, potfiromycin, puromycin, quelamycin,rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex,zinostatin, zorubicin; anti-metabolites such as methotrexate and5-fluorouracil (5-FU); folic acid analogues such as denopterin,methotrexate, pteropterin, trimetrexate; purine analogs such asfludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidineanalogs such as ancitabine, azacitidine, 6-azauridine, carmofur,cytarabine, dideoxyuridine, doxifluridine, enocitabine, floxuridine;androgens such as calusterone, dromostanolone propionate, epitiostanol,mepitiostane, testolactone; anti-adrenals such as aminoglutethimide,mitotane, trilostane; folic acid replenisher such as frolinic acid;aceglatone; aldophosphamide glycoside; aminolevulinic acid; eniluracil;amsacrine; bestrabucil; bisantrene; edatraxate; defofamine; demecolcine;diaziquone; elformithine; elliptinium acetate; an epothilone; etoglucid;gallium nitrate; hydroxyurea; lentinan; lonidainine; maytansinoids suchas maytansine and ansamitocins; mitoguazone; mitoxantrone; mopidanmol;nitraerine; pentostatin; phenamet; pirarubicin; losoxantrone;podophyllinic acid; 2-ethylhydrazide; procarbazine; PSK® polysaccharidecomplex (JHS Natural Products, Eugene, Oreg.); razoxane; rhizoxin;sizofuran; spirogermanium; tenuazonic acid; triaziquone;2,2′,2″-trichlorotriethylamine; trichothecenes (especially T-2 toxin,verracurin A, roridin A and anguidine); urethan; vindesine; dacarbazine;mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine;arabinoside (“Ara-C”); cyclophosphamide; thiotepa; taxoids, e.g., TAXOL®paclitaxel (Bristol-Myers Squibb Oncology, Princeton, N.J.), ABRAXANE®Cremophor-free, albumin-engineered nanoparticle formulation ofpaclitaxel (American Pharmaceutical Partners, Schaumberg, Ill.), andTAXOTERE® doxetaxel (Rhone-Poulenc Rorer, Antony, France); chloranbucil;GEMZAR® gemcitabine; 6-thioguanine; mercaptopurine; methotrexate;platinum analogs such as cisplatin, oxaliplatin and carboplatin;vinblastine; platinum; etoposide (VP-16); ifosfamide; mitoxantrone;vincristine; NAVELBINE, vinorelbine; novantrone; teniposide; edatrexate;daunomycin; aminopterin; xeloda; ibandronate; irinotecan (Camptosar,CPT-11) (including the treatment regimen of irinotecan with 5-FU andleucovorin); topoisomerase inhibitor RFS 2000; difluoromethylornithine(DMFO); retinoids such as retinoic acid; capecitabine; combretastatin;leucovorin (LV); oxaliplatin, including the oxaliplatin treatmentregimen (FOLFOX); lapatinib (TYKERB); inhibitors of PKC-alpha, Raf,H-Ras, EGFR (e.g., erlotinib (TARCEVA®)) and VEGF-A that reduce cellproliferation and pharmaceutically acceptable salts, acids orderivatives of any of the above. In addition, the methods of treatmentcan further include the use of radiation, radiotherapy, or radiationtherapy.

As used herein, the terms “chemotherapy” or “chemotherapeutic agent”refer to any chemical agent with therapeutic usefulness in the treatmentof diseases characterized by abnormal cell growth. Such diseases includetumors, neoplasms and cancer as well as diseases characterized byhyperplastic growth. Chemotherapeutic agents as used herein encompassboth chemical and biological agents. These agents function to inhibit acellular activity upon which the cancer cell depends for continuedsurvival. Categories of chemotherapeutic agents includealkylating/alkaloid agents, antimetabolites, hormones or hormoneanalogs, and miscellaneous antineoplastic drugs. Most if not all ofthese agents are directly toxic to cancer cells and do not requireimmune stimulation. In one embodiment, a chemotherapeutic agent is anagent of use in treating neoplasms such as solid tumors. In oneembodiment, a chemotherapeutic agent is a radioactive molecule. One ofskill in the art can readily identify a chemotherapeutic agent of use(e.g. see Slapak and Kufe, Principles of Cancer Therapy, Chapter 86 inHarrison's Principles of Internal Medicine, 14th edition; Perry et al.,Chemotherapy, Ch. 17 in Abeloff, Clinical Oncology 2, 2000 ChurchillLivingstone, Inc; Baltzer L, Berkery R (eds): Oncology Pocket Guide toChemotherapy, 2nd ed. St. Louis, Mosby-Year Book, 1995; Fischer D S,Knobf M F, Durivage H J (eds): The Cancer Chemotherapy Handbook, 4th ed.St. Louis, Mosby-Year Book, 1993).

By “radiation therapy” is meant the use of directed gamma rays or betarays to induce sufficient damage to a cell so as to limit its ability tofunction normally or to destroy the cell altogether. It will beappreciated that there will be many ways known in the art to determinethe dosage and duration of treatment. Typical treatments are given as aone time administration and typical dosages range from 10 to 200 units(Grays) per day.

In some embodiments of these methods and all such methods describedherein, the methods further comprise administering a tumor or cancerantigen to a subject being administered the LAP binding agent(s)described herein. The antigen can be administered as a tumor antigenvaccine. In addition to known tumor antigen expressed by a subject'stumor, whole tumor antigen vaccination is also contemplated. See, e.g.,Chiang et al, Vaccines 3: 344-372 (2015).

A number of tumor antigens have been identified that are associated withspecific cancers. As used herein, the terms “tumor antigen” and “cancerantigen” are used interchangeably to refer to antigens which aredifferentially expressed by cancer cells and can thereby be exploited inorder to target cancer cells. Cancer antigens are antigens which canpotentially stimulate apparently tumor-specific immune responses. Someof these antigens are encoded, although not necessarily expressed, bynormal cells. These antigens can be characterized as those which arenormally silent (i.e., not expressed) in normal cells, those that areexpressed only at certain stages of differentiation and those that aretemporally expressed such as embryonic and fetal antigens. Other cancerantigens are encoded by mutant cellular genes, such as oncogenes (e.g.,activated ras oncogene), suppressor genes (e.g., mutant p53), and fusionproteins resulting from internal deletions or chromosomaltranslocations. Still other cancer antigens can be encoded by viralgenes such as those carried on RNA and DNA tumor viruses. Many tumorantigens have been defined in terms of multiple solid tumors: MAGE 1, 2,& 3, defined by immunity; MART-1/Melan-A, gp100, carcinoembryonicantigen (CEA), HER-2, mucins (i.e., MUC-1), prostate-specific antigen(PSA), and prostatic acid phosphatase (PAP). In addition, viral proteinssuch as hepatitis B (HBV), Epstein-Barr (EBV), and human papilloma (HPV)have been shown to be important in the development of hepatocellularcarcinoma, lymphoma, and cervical cancer, respectively. However, tumorsuse or benefit from a range of different immune evasion mechanisms, suchthat the immune systems of cancer patients often fail to respond to thetumor antigens. Some examples of cancer antigens that are normallyassociated with spermatocytes or spermatogonia of the testis, placenta,and ovary include the cancer-testis (CT) antigens BAGE, GAGE, MAGE-1 andMAGE-3, NY-ESO-1, SSX. These antigens are found in melanoma, lymphoma,lung, bladder, colon, and breast carcinomas (e.g., as described inButterfield et al., J. Immunotherapy 2008; 31:294-309; Markowicz et al.,J Clin Oncol 27:15s, 2009 (suppl; abstr 9039)). Cancer antigens normallyfound in melanocytes, epithelial tissues, prostate, and colon alsoinclude the differentiation antigens Gp100, Melan-A/Mart-1, Tyrosinase,PSA, CEA, and Mammaglobin-A. These antigens are found in melanoma,prostate cancer, and in colon and breast carcinomas. Some cancerantigens are shared antigens that are ubiquitously expressed at lowlevels but overexpressed in cancers. Examples of overexpressed cancerantigens include p53, HER-2/neu, livin, and survivin, found inesophagus, liver, pancreas, colon, breast, ovary, bladder, and prostatecarcinomas. Other cancer antigens are unique, such as β-catenin-m,β-Actin/4/m, Myosin/m, HSP70-2/m, and HLA-A2-R170J, which are associatedwith one or more of melanoma, non-small cell lung cancer, and renalcancer. Still other cancer antigens are the tumor-associatedcarbohydrate antigens that are normally found in epithelia tissues suchas renal, intestinal, and colorectal tissues. These cancer antigensinclude GM2, GD2, GD3, MUC-1, sTn, abd globo-H, which can be found inmelanoma, neuroblastoma, colorectal, lung, breast, ovarian, and prostatecancers. Additional tumor antigens, peptide epitopes, and descriptionsthereof are described in U.S. Pat. Nos. 7,906,620; 7,910,692; 8,097,242;7,935,531; 8,012,468; 8,097,256; 8,003,773; Tartour et al., Immunol Lett2000; 74(1): 1-3, the contents of which are herein incorporated byreference in their entireties. In some embodiments, the intact cancerantigen is used, whereas in other embodiments, a peptide epitope of thecancer antigen (prepared either by proteolytic digestion orrecombinantly) is used. Accordingly, non-limiting examples of tumor orcancer antigens for use with the compositions and methods describedherein include, but are not limited to, Her2, prostate stem cell antigen(PSCA), PSMA (prostate-specific membrane antigen), β-catenin-m, B cellmaturation antigen (BCMA), alpha-fetoprotein (AFP), carcinoembryonicantigen (CEA), cancer antigen-125 (CA-125), CA19-9, calretinin, MUC-1,epithelial membrane protein (EMA), epithelial tumor antigen (ETA),tyrosinase, Mammaglobin-A, melanoma-associated antigen (MAGE), CD34,CD45, CD99, CD117, chromogranin, cytokeratin, desmin, glial fibrillaryacidic protein (GFAP), gross cystic disease fluid protein (GCDFP-15),EBV, gp100, HMB-45 antigen, protein melan-A (melanoma antigen recognizedby T lymphocytes; MART-1), livin, survivin, myo-D1, muscle-specificactin (MSA), neurofilament, neuron-specific enolase (NSE), placentalalkaline phosphatase, synaptophysin, thyroglobulin, thyroidtranscription factor-1, the dimeric form of the pyruvate kinaseisoenzyme type M2 (tumor M2-PK), CD19, CD22, CD27, CD30, CD70, GD2(ganglioside G2), EphA2, CSPG4, CD138, FAP (Fibroblast ActivationProtein), CD171, kappa, lambda, 5T4, α_(v)β₆ integrin, B7-H3, B7-H6,CAIX, CD19, CD20, CD22, CD30, CD33, CD44, CD44v6, CD44v7/8, CD70, CD123,EGFR, EGP2, EGP40, EpCAM, fetal AchR, FRα, GAGE, GD3, HLA-A1+MAGE1,MAGE-3, HLA-A1+NY-ESO-1, IL-11Rα, IL-13Rα2, Lewis-Y, Muc16, NCAM, NKG2DLigands, NY-ESO-1, PRAME, ROR1, SSX, Survivin, TAG72, TEMs, VEGFR2,EGFRvIII (epidermal growth factor variant III), sperm protein 17 (Sp17),mesothelin, PAP (prostatic acid phosphatase), prostein, TARP (T cellreceptor gamma alternate reading frame protein), Trp-p8, STEAP1(six-transmembrane epithelial antigen of the prostate 1), HSP70-2/m, andHLA-A2-R170J, tyrosinase, an abnormal ras protein, or an abnormal p53protein.

In some embodiments of these methods and all such methods describedherein, the methods further comprise administering a dendritic cell (DC)vaccination concurrently or in combination with the LAP binding agent(s)described herein.

As used herein “dendritic cell vaccination” or a “DC vaccine” refers toa form of immunotherapy designed to induce T cell-dependent immunity,such as cancer-specific T cell-dependent anti-tumor immunity, that canresult in durable complete responses using DCs. Examples of “dendriticcell (DC) immunotherapies” or “dendritic cell vaccines,” as used herein,include modified dendritic cells and any other antigen presenting cell,autologous or xeno, whether modified by multiple antigens, whole cancercells, single antigens, by mRNA, phage display or any othermodification, including, but not restricted to, ex vivo-generated,antigen-loaded dendritic cells (DCs) to induce antigen-specific T-cellimmunity, ex vivo gene-loaded DCs to induce humoral immunity, exvivo-generated, antigen-loaded DCs to induce tumour-specific immunity,ex vivo-generated immature DCs to induce tolerance, for example.

By “reduce,” “inhibit” or “decrease” in terms of the values and cancertreatment methods described herein is meant the ability to cause anoverall decrease preferably of 20% or greater, 30% or greater, 40% orgreater, 45% or greater, more preferably of 50% or greater, of 55% orgreater, of 60% or greater, of 65% or greater, of 70% or greater, andmost preferably of 75% or greater, 80% or greater, 85% or greater, 90%or greater, or 95% or greater, for a given parameter or symptom. Reduce,inhibit or decrease can refer to, for example, the symptoms of thedisorder being treated, the presence or size of metastases ormicrometastases, the size of a primary tumor, the number or activity ofa certain cell population, etc.

As used herein, “alleviating a symptom of a cancer or tumor” isameliorating any condition or symptom associated with the cancer such asthe symptoms of the cancer being treated, the presence or size ofmetastases or micrometastases, the size of the primary tumor, thepresence or the size of the dormant tumor, etc. As compared with anequivalent untreated control, such as a subject prior to theadministration of the LAP binding agents, such reduction or degree ofprevention is at least 5%, 10%, 20%, 40%, 50%, 60%, 80%, 90%, 95%, ormore as measured by any standard technique known to one of ordinaryskill in the art. A patient or subject who is being treated for a canceror tumor is one who a medical practitioner has diagnosed as having sucha condition. Diagnosis can be by any suitable means.

As used herein, in regard to any of the compositions, methods, and usescomprising LAP binding agents described herein, the terms “treat,”“treatment,” “treating,” or “amelioration” refer to therapeutictreatments, wherein the object is to reverse, alleviate, ameliorate,inhibit, slow down or stop the progression or severity of a conditionassociated with, a disease or disorder. The term “treating” includesreducing or alleviating at least one adverse effect or symptom of adisease or disorder. Treatment is generally “effective” if one or moresymptoms or clinical markers are reduced. Alternatively, treatment is“effective” if the progression of a disease is reduced or halted. Thatis, “treatment” includes not just the improvement of symptoms ormarkers, but also a cessation of at least slowing of progress orworsening of symptoms that would be expected in absence of treatment.Beneficial or desired clinical results include, but are not limited to,alleviation of one or more symptom(s), diminishment of extent ofdisease, stabilized (i.e., not worsening) state of disease, delay orslowing of disease progression, amelioration or palliation of thedisease state, and remission (whether partial or total), whetherdetectable or undetectable. The term “treatment” of a disease alsoincludes providing relief from the symptoms or side-effects of thedisease (including palliative treatment).

The terms “subject,” “patient,” and “individual” as used in regard toany of the methods described herein are used interchangeably herein, andrefer to an animal, for example a human, recipient of the inhibitorsdescribed herein. For treatment of disease states which are specific fora specific animal such as a human subject, the term “subject” refers tothat specific animal. The terms “non-human animals” and “non-humanmammals” are used interchangeably herein, and include mammals such asrats, mice, rabbits, sheep, cats, dogs, cows, pigs, and non-humanprimates. The term “subject” also encompasses any vertebrate includingbut not limited to mammals, reptiles, amphibians and fish. However,advantageously, the subject is a mammal such as a human, or othermammals such as a domesticated mammal, e g dog, cat, horse, and thelike. Production mammal, e.g. cow, sheep, pig, and the like are alsoencompassed in the term subject.

The term “effective amount” as used herein refers to the amount of a LAPbinding agent described herein, needed to alleviate at least one or moresymptom of the disease or disorder being treated, and relates to asufficient amount of pharmacological composition to provide the desiredeffect, e.g., reduce or inhibit LAP-mediated tumor immune suppression.The term “therapeutically effective amount” therefore refers to anamount of the inhibitors or potentiators described herein, using themethods as disclosed herein, that is sufficient to provide a particulareffect when administered to a typical subject. An effective amount asused herein would also include an amount sufficient to delay thedevelopment of a symptom of the disease, alter the course of a symptomdisease (for example but not limited to, slow the progression of asymptom of the disease), or reverse a symptom of the disease. Thus, itis not possible to specify the exact “effective amount”. However, forany given case, an appropriate “effective amount” can be determined byone of ordinary skill in the art using only routine experimentation.

Effective amounts, toxicity, and therapeutic efficacy can be determinedby standard pharmaceutical procedures in cell cultures or experimentalanimals, e.g., for determining the LD50 (the dose lethal to 50% of thepopulation) and the ED50 (the dose therapeutically effective in 50% ofthe population). The dosage can vary depending upon the dosage formemployed and the route of administration utilized. The dose ratiobetween toxic and therapeutic effects is the therapeutic index and canbe expressed as the ratio LD50/ED50. Compositions, methods, and usesthat exhibit large therapeutic indices are preferred. A therapeuticallyeffective dose can be estimated initially from cell culture assays.Also, a dose can be formulated in animal models to achieve a circulatingplasma concentration range that includes the IC50, which achieves ahalf-maximal inhibition of measured function or activity) as determinedin cell culture, or in an appropriate animal model. Levels in plasma canbe measured, for example, by high performance liquid chromatography. Theeffects of any particular dosage can be monitored by a suitablebioassay. The dosage can be determined by a physician and adjusted, asnecessary, to suit observed effects of the treatment.

The LAP binding agents described herein can be administered to a subjectin need thereof by any appropriate route which results in an effectivetreatment in the subject. As used herein, the terms “administering,” and“introducing” are used interchangeably and refer to the placement of LAPbinding agents into a subject by a method or route which results in atleast partial localization of such agents at a desired site, such as atumor site or site of inflammation, such that a desired effect(s) isproduced.

In some embodiments, the LAP binding agents described herein can beadministered to a subject by any mode of administration that deliversthe agent systemically or to a desired surface or target, and caninclude, but is not limited to, injection, infusion, instillation, andinhalation administration. To the extent that polypeptide agents can beprotected from inactivation in the gut, oral administration forms arealso contemplated. “Injection” includes, without limitation,intravenous, intramuscular, intraarterial, intrathecal,intraventricular, intracapsular, intraorbital, intracardiac,intradermal, intraperitoneal, transtracheal, subcutaneous, subcuticular,intraarticular, sub capsular, subarachnoid, intraspinal, intracerebrospinal, and intrasternal injection and infusion.

The phrases “parenteral administration” and “administered parenterally”as used herein, refer to modes of administration other than enteral andtopical administration, usually by injection. The phrases “systemicadministration,” “administered systemically”, “peripheraladministration” and “administered peripherally” as used herein refer tothe administration of LAP binding agents, other than directly into atarget site, tissue, or organ, such that it enters the subject'scirculatory system and, thus, is subject to metabolism and other likeprocesses.

Some embodiments of the present invention may be defined in any of thefollowing numbered paragraphs:

-   1. An isolated anti-LAP (latency associated peptide) antibody or    antigen-binding fragment thereof that specifically binds to LAP    comprising one or more heavy and light chain complimentarity    determining regions (CDRs) selected from the group consisting of:

a. a heavy chain CDR1 having the amino acid sequence of SEQ ID NO: 9;

b. a heavy chain CDR2 having the amino acid sequence of SEQ ID NO: 10;

c. a heavy chain CDR3 having the amino acid sequence of SEQ ID NO: 11;

d. a light chain CDR1 having the amino acid sequence of SEQ ID NO: 14;

e. a light chain CDR2 having the amino acid sequence of SEQ ID NO: 15;and

f. a light chain CDR3 having the amino acid sequence of SEQ ID NO: 16.

-   2. The isolated anti-LAP antibody or antigen-binding fragment    thereof of paragraph 1, comprising the heavy chain complimentarity    determining regions (CDRs):

a. a heavy chain CDR1 having the amino acid sequence of SEQ ID NO: 9;

b. a heavy chain CDR2 having the amino acid sequence of SEQ ID NO: 10;and

c. a heavy chain CDR3 having the amino acid sequence of SEQ ID NO: 11.

-   3. The isolated anti-LAP antibody or antigen-binding fragment    thereof of any one of paragraphs 1-2, comprising the light chain    complimentarity determining regions (CDRs):

a. a light chain CDR1 having the amino acid sequence of SEQ ID NO: 14;

b. a light chain CDR2 having the amino acid sequence of SEQ ID NO: 15;and

c. a light chain CDR3 having the amino acid sequence of SEQ ID NO: 16.

-   4. The isolated anti-LAP antibody or antigen-binding fragment    thereof of any one of paragraphs 1-2, comprising the complimentarity    determining regions (CDRs):

a. a heavy chain CDR1 having the amino acid sequence of SEQ ID NO: 9;

b. a heavy chain CDR2 having the amino acid sequence of SEQ ID NO: 10;

c. a heavy chain CDR3 having the amino acid sequence of SEQ ID NO: 11;

d. a light chain CDR1 having the amino acid sequence of SEQ ID NO: 14;

e. a light chain CDR2 having the amino acid sequence of SEQ ID NO: 15;and

f. a light chain CDR3 having the amino acid sequence of SEQ ID NO: 16.

-   5. The isolated anti-LAP antibody or antigen-binding fragment    thereof of any one of paragraphs 1-4, comprising a heavy chain    having the amino acid sequence of SEQ ID NO: 8.-   6. The isolated anti-LAP antibody or antigen-binding fragment    thereof of any one of paragraphs 1-5, comprising a light chain    having the sequence of SEQ ID NO: 13.-   7. An isolated anti-LAP antibody or antigen-binding fragment thereof    that specifically binds LAP comprising:

a. a heavy chain CDR1 having the amino acid sequence of SEQ ID NO: 9;

b. a heavy chain CDR2 having the amino acid sequence of SEQ ID NO: 10;

c. a heavy chain CDR3 having the amino acid sequence of SEQ ID NO: 11;

d. a light chain CDR1 having the amino acid sequence of SEQ ID NO: 14;

e. a light chain CDR2 having the amino acid sequence of SEQ ID NO: 15;and

f. a light chain CDR3 having the amino acid sequence of SEQ ID NO: 16.

-   8. An isolated anti-LAP antibody or antigen-binding fragment thereof    that specifically binds to LAP comprising one or more heavy chain    complimentarity determining regions (CDRs) selected from the group    consisting of:

a. a heavy chain CDR1 having the amino acid sequence of SEQ ID NO: 9;

b. a heavy chain CDR2 having the amino acid sequence of SEQ ID NO: 10;and

c. a heavy chain CDR3 having the amino acid sequence of SEQ ID NO: 11.

-   9. An isolated anti-LAP antibody or antigen-binding fragment thereof    that specifically binds to LAP comprising one or more light chain    complimentarity determining regions (CDRs) selected from the group    consisting of:

a. a light chain CDR1 having the amino acid sequence of SEQ ID NO: 14;

b. a light chain CDR2 having the amino acid sequence of SEQ ID NO: 15;and

c. a light chain CDR3 having the amino acid sequence of SEQ ID NO: 16.

-   10. The isolated anti-LAP antibody or antigen-binding fragment    thereof of any one of paragraphs 1-9, wherein the antibody is a    chimeric, CDR-grafted, humanized, composite human or fully human    antibody or dual antibody or antigen-binding fragment thereof.-   11. The isolated anti-LAP antibody or antigen-binding fragment    thereof of any one of paragraphs 1-10, wherein the antibody fragment    is a Fab fragment, a Fab′ fragment, a Fd fragment, a Fd′ fragment, a    Fv fragment, a dAb fragment, a F(ab′)₂ fragment, a single chain    fragment, a diabody, or a linear antibody.-   12. The isolated anti-LAP antibody or antigen-binding fragment    thereof of any one of paragraphs 1-10, wherein the antibody or    antibody fragment thereof comprises a human acceptor framework.-   13. A composition comprising a LAP-binding agent and an inhibitor of    TGF-β signaling.-   14. The composition of paragraph 13, wherein the LAP-binding agent    comprises an anti-LAP antibody or antigen-binding fragment thereof.-   15. The composition of paragraph 14, wherein the antibody is a    monoclonal antibody.-   16. The composition of paragraph 14, wherein the antibody is    chimeric, CDR-grafted, humanized or fully human.-   17. The composition of paragraph 14, wherein the anti-LAP antibody    or antigen-binding fragment thereof is selected from those of    paragraphs 1-12.-   18. The composition of paragraph 13, wherein the inhibitor of TGF-β    signaling is selected from the group consisting of an antibody or    antigen-binding fragment thereof that binds TGF-β or a receptor    therefor, a double-stranded RNA or nucleic acid encoding a    double-stranded RNA, an aptamer, and a small molecule.-   19. The composition of paragraph 18, wherein the small molecule is    selected from the group consisting of    4-[4-(1,3-benzodioxol-5-yl)-5-pyridin-2-yl-1H-imidazol-2-yl]benzamide    (SB431542),    N-(oxan-4-yl)-4-[4-(5-pyridin-2-yl-1H-pyrazol-4-yl)pyridin-2-yl]benzamide    (GW788388), 4-[3-(2-Pyridinyl)-1H-pyrazol-4-yl]-quinoline    (LY364947), and    2-(3-(6-methylpyridin-2-yl)-1H-pyrazol-4-yl)-1,5-naphthyridine    (“ALK5 Inhibitor II”).-   20. A composition comprising a LAP-binding agent and an    immunomodulatory or chemotherapeutic agent.-   21. The composition of paragraph 20, wherein the LAP-binding agent    comprises an antibody or antigen-binding fragment thereof.-   22. The composition of paragraph 21, wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   23. The composition of paragraph 21, wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   24. The composition of paragraph 21, wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   25. The composition of paragraph 20, wherein the immunomodulatory    agent comprises an immune checkpoint modulator.-   26. The composition of paragraph 25, wherein the immune checkpoint    modulator modulates the effects of a polypeptide selected from the    group consisting of PD-1, PD-L1, PDL2, CTLA4, LAG3, TIM3, TIGIT,    and/or CD103.-   27. The composition of paragraph 20, wherein the immunomodulatory    agent comprises a tumor antigen vaccine.-   28. The composition of paragraph 27, wherein the tumor antigen    vaccine comprises a dendritic cell tumor antigen vaccine.-   29. An antibody or antigen-binding fragment thereof that binds to    LAP when complexed with TGF-β and inhibits release of TGF-β from the    LAP/TGF-β complex.-   30. The composition of paragraph 29, wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   31. The composition of paragraph 29, wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   32. The composition of paragraph 29, wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   33. The antibody or antigen-binding fragment of paragraph 29, which    binds an epitope formed by the binding of LAP to TGF-β.-   34. The antibody or antigen-binding fragment of paragraph 29, which    comprises the CDRs of the antibody of paragraph 7.-   35. A pharmaceutical composition comprising the composition of any    one of paragraphs 1-34, and a pharmaceutically acceptable carrier.-   36. A method of decreasing the number or activity of a population of    LAP+ T Regulatory cells in a subject, the method comprising    administering a LAP-binding agent to the subject, whereby the number    or activity of the population is decreased.-   37. The method of paragraph 36, wherein the LAP-binding agent    comprises an antibody or antigen-binding fragment thereof.-   38. The method of paragraph 37, wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   39. The method of paragraph 37, wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   40. The method of paragraph 37, wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   41. The method of paragraph 36, wherein the LAP-binding agent is    conjugated to a cytotoxic drug.-   42. A method of decreasing the number or activity of    tumor-infiltrated immunosuppressive T cells in a tumor, the method    comprising administering a LAP-binding agent to a subject with a    tumor comprising tumor-infiltrated immunosuppressive T cells,    whereby the number or activity of such cells is decreased.-   43. The method paragraph 42, wherein the LAP-binding agent comprises    an antibody or antigen-binding fragment thereof.-   44. The method of paragraph 43, wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   45. The method of paragraph 43, wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   46. The method of paragraph 43, wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   47. The method of paragraph 42, wherein the LAP-binding agent is    conjugated to a cytotoxic drug.-   48. A method of increasing tumor-specific immunity comprising    administering a therapeutically effective amount of a LAP-binding    agent to a subject in need thereof.-   49. The method paragraph 48, wherein the LAP-binding agent comprises    an antibody or antigen-binding fragment thereof.-   50. The method of paragraph 49, wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   51. The method of paragraph 49, wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   52. The method of paragraph 49, wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   53. A method of treating a cancer or tumor where LAP expression    and/or activity is associated with suppression of cancer- or    tumor-specific immunity comprising administering a therapeutically    effective amount of a LAP-binding agent to a subject in need    thereof.-   54. The method paragraph 53, wherein the LAP-binding agent comprises    an antibody or antigen-binding fragment thereof.-   55. The method of paragraph 54, wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   56. The method of paragraph 54, wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   57. The method of paragraph 54, wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   58. A method of increasing the number of CD8+ cytotoxic T cells in a    tumor, the method comprising administering, to a subject with a    tumor, a LAP-binding agent.-   59. The method paragraph 58, wherein the LAP-binding agent comprises    an antibody or antigen-binding fragment thereof.-   60. The method of paragraph 59, wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   61. The method of paragraph 59, wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   62. The method of paragraph 59, wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   63. A method of increasing peripheral CD4+ T cells expressing IFNγ    in a subject in need thereof, the method comprising administering a    LAP-binding agent to the subject.-   64. The method paragraph 63 wherein the LAP-binding agent comprises    an antibody or antigen-binding fragment thereof.-   65. The method of paragraph 64 wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   66. The method of paragraph 64 wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   67. The method of paragraph 64 wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   68. A method of increasing peripheral CD8+ T cells expressing    granzyme B in a subject in need thereof, the method comprising    administering a LAP-binding agent to the subject.-   69. The method paragraph 68 wherein the LAP-binding agent comprises    an antibody or antigen-binding fragment thereof.-   70. The method of paragraph 69 wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   71. The method of paragraph 69 wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   72. The method of paragraph 69 wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   73. A method of decreasing the number of FoxP3+ regulatory T cells    in a tumor, the method comprising administering a LAP-binding agent    to the subject.-   74. The method paragraph 73 wherein the LAP-binding agent comprises    an antibody or antigen-binding fragment thereof.-   75. The method of paragraph 74 wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   76. The method of paragraph 74 wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   77. The method of paragraph 74 wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   78. A method of inhibiting expression of an immunosuppressive factor    or marker by CD8+ and/or CD4+ T cells in a tumor, the method    comprising administering a LAP-binding agent to a subject with a    tumor.-   79. The method paragraph 78 wherein the LAP-binding agent comprises    an antibody or antigen-binding fragment thereof.-   80. The method of paragraph 79 wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   81. The method of paragraph 79 wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   82. The method of paragraph 79 wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   83. The method of paragraph 78 wherein the immunosuppressive factor    or marker comprises one or more of PD-1, LAG-3 and CD103.-   84. A method of promoting an anti-tumor immune response, the method    comprising vaccinating a subject in need of treatment for a tumor    with a tumor antigen and administering a LAP-binding agent to the    subject.-   85. The method paragraph 84 wherein the LAP-binding agent comprises    an antibody or antigen-binding fragment thereof.-   86. The method of paragraph 85 wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   87. The method of paragraph 85 wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   88. The method of paragraph 85 wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   89. A method of treating cancer that is refractory to treatment with    an immune checkpoint inhibitor, the method comprising administering    to a subject having such cancer a LAP-binding agent.-   90. The method paragraph 89 wherein the LAP-binding agent comprises    an antibody or antigen-binding fragment thereof.-   91. The method of paragraph 90 wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   92. The method of paragraph 90 wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   93. The method of paragraph 90 wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   94. The method of paragraph 89, further comprising administering an    immune checkpoint inhibitor.-   95. The method of paragraph 89, wherein the cancer is a    glioblastoma, colorectal carcinoma or a melanoma.-   96. The method of paragraph 89, wherein the cancer is refractory to    a PD-1 or PD-L1 inhibitor before treatment with the LAP-binding    agent.-   97. A method for treating cancer, the method comprising analyzing a    tumor sample from a subject to determine the presence of LAP+ T    regulatory cells, and, if LAP+ T regulatory cells are present,    administering to the subject a LAP-binding agent, thereby promoting    an anti-tumor immune response.-   98. The method paragraph 97 wherein the LAP-binding agent comprises    an antibody or antigen-binding fragment thereof.-   99. The method of paragraph 97 wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   100. The method of paragraph 97 wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human-   101. The method of paragraph 97 wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   102. A method of selecting a patient, from among a population of    cancer patients, whose cancer is likely to respond to therapy with a    LAP-binding agent, the method comprising analyzing a tumor sample    from a patient for the presence of LAP+ T regulatory cells, wherein,    if LAP+ T regulatory cells are found to be present in the patient's    tumor, the patient's tumor is identified as likely to respond to    therapy with a LAP-binding agent.-   103. The method of paragraph 102, further comprising, when LAP+ T    regulatory cells are found in said tumor, administering a    LAP-binding agent to that patient, and when LAP+ T regulatory cells    are not found in said tumor, administering an immunomodulatory or    anti-tumor agent other than a LAP-binding agent to the patient.-   104. The method paragraph 102 or 103 wherein the LAP-binding agent    comprises an antibody or antigen-binding fragment thereof.-   105. The method of paragraph 104 wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   106. The method of paragraph 104 wherein the antibody or    antigen-binding fragment thereof is chimeric, CDR-grafted, humanized    or fully human.-   107. The method of paragraph 104 wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   108. The method of paragraph 102, wherein the analysis of a tumor    sample from the patient for the presence of LAP+ T regulatory cells    comprises quantitative measurement of the amount of LAP+T regulatory    cells present, and when LAP+ T regulatory cells are found to be    present, comparing their amount to a reference, wherein a tumor with    a higher relative level of LAP+ T regulatory cells is identified as    more likely to respond to therapy with a LAP-binding agent.-   109. The method of paragraph 103 wherein the immunomodulatory agent    comprises an immune checkpoint inhibitor.-   110. The method of paragraph 103 wherein the anti-tumor agent    comprises gamma radiation or a chemotherapeutic agent.-   111. A method of promoting the formation of memory T cells specific    for an antigen of interest in a subject in need thereof, the method    comprising administering a LAP-binding agent and the antigen of    interest to the subject.-   112. The method of paragraph 111 wherein CD44+ and/or IL7R+ T cells    are increased following administration of the LAP-binding agent.-   113. The method of paragraph 111 wherein the antigen of interest    comprises a tumor antigen or an antigen expressed by an infectious    pathogen.-   114. The method of paragraph 113 wherein the tumor antigen is    administered as a dendritic cell vaccine.-   115. The method paragraph 111 wherein the LAP-binding agent    comprises an antibody or antigen-binding fragment thereof.-   116. The method of paragraph 115 wherein the antibody or    antigen-binding fragment thereof is a monoclonal antibody or    antigen-binding fragment thereof.-   117. The method of paragraph 115 wherein the antibody or    antigen-binding fragment thereof is chimeric, humanized or fully    human-   118. The method of paragraph 115 wherein the antibody or    antigen-binding fragment thereof comprises an antibody composition    of any one of paragraphs 1-12.-   119. Use of a LAP-binding agent to treat a disease or disorder    characterized by or involving an undesirable number or activity of    LAP+ T regulatory cells.-   120. Use of a LAP-binding agent to decrease the number or activity    of tumor-infiltrated immunosuppressive T cells in a tumor, the use    comprising administering a LAP-binding agent to a subject with a    tumor comprising tumor-infiltrated immunosuppressive T cells,    whereby the number or activity of such cells is decreased.-   121. Use of a LAP-binding agent to increase tumor-specific immunity,    the use comprising administering a therapeutically effective amount    of a LAP-binding agent to a subject in need thereof.-   122. Use of a LAP-binding agent for the treatment of a cancer or    tumor where LAP expression and/or activity is associated with    suppression of cancer- or tumor-specific immunity, the use    comprising administering a therapeutically effective amount of a    LAP-binding agent to a subject in need thereof.-   123. Use of a LAP-binding agent for the treatment of a cancer or    tumor by increasing the number of CD8+ cytotoxic T cells in a tumor,    the use comprising administering, to a subject with a tumor, a    LAP-binding agent.-   124. Use of a LAP-binding agent for the treatment of a cancer or    tumor by increasing peripheral CD4+ T cells expressing IFNγ in a    subject in need thereof, the use comprising administering a    LAP-binding agent to the subject.-   125. Use of a LAP-binding agent for the treatment of a cancer or    tumor by increasing peripheral CD8+ T cells expressing granzyme B in    a subject in need thereof, the use comprising administering a    LAP-binding agent to the subject.-   126. Use of a LAP-binding agent for the treatment of a cancer or    tumor by decreasing the number of FoxP3+ regulatory T cells in a    tumor, the use comprising administering a LAP-binding agent to the    subject.-   127. Use of a LAP-binding agent for the treatment of a cancer or    tumor by inhibiting expression of an immunosuppressive factor by    CD8+ and/or CD4+ T cells in a tumor, the use comprising    administering a LAP-binding agent to a subject with a tumor.-   128. Use of a LAP-binding agent for promoting an anti-tumor immune    response, the use comprising vaccinating a subject in need of    treatment for a tumor with a tumor antigen and administering a    LAP-binding agent to the subject.-   129. Use of a LAP-binding agent for treating cancer that is    refractory to treatment with an immune checkpoint inhibitor, the use    comprising administering to a subject having such cancer a    LAP-binding agent.-   130. Use of a LAP-binding agent for treating cancer, the use    comprising analyzing a tumor sample from a subject to determine the    presence of LAP+ T regulatory cells, and, if LAP+ T regulatory cells    are present, administering to the subject a LAP-binding agent,    thereby promoting an anti-tumor immune response.-   131. Use of a LAP-binding agent promoting the formation of memory T    cells specific for an antigen of interest for the treatment of    cancer or an infection in a subject, the use comprising    administering a LAP-binding agent and the antigen of interest to the    subject.-   132. The composition of any one of paragraphs 13-32 or the method of    any one of paragraphs 36-118 or the use of any one of paragraphs    119-131 wherein the LAP-binding agent specifically binds a LAP    molecule having the sequence set forth in any one of SEQ ID NOs:    1-3.-   133. The composition of any one of paragraphs 13-28 or the method of    any one of paragraphs 37, 43, 49, 54, 59, 64, 69, 74, 79, 85, 90,    98, 104 or 115 wherein the antibody or antigen-binding fragment    thereof binds a LAP ligand interaction site.-   134. The composition or method of paragraph 133, wherein the LAP    ligand interaction site is a site that interacts with mature TGFβ, a    site that interacts with integrins, and/or a site that interacts    with latent TGFβ binding protein (LTBP).-   135. The composition of any one of paragraphs 1-28 or the method of    any one of paragraphs 36, 42, 48, 53, 58, 63, 68, 73, 78, 84, 89,    97, 102, 111 or the use of any one of paragraphs 119-131 wherein the    LAP-binding agent binds LAP complexed with TGF-β and inhibits    release of TGF-β from the complex.-   136. The composition of any one of paragraphs 15, 22, 30, or the    method of any one of paragraphs 38, 44, 50, 55, 60, 65, 70, 75, 80,    86, 91, 99, 105 or 116 wherein the monoclonal antibody is produced    by any one of the hybridoma clones selected from TW4-9E7, TW4-5A8,    TW4-3E5, TW4-4E5, TW4-12B12, TW4-13B12, TW4-1G12, TW4-3G5, TW4-2F8,    TW4-6H10, TW4-1G2, TW4-1E1, TW4-16F4, TW4-8F10, TW4-3H6, TW4-2C9,    TW7-16B4, TW7-28G11, TW7-7H4, and TW7-20B9.-   137. The composition of any one of paragraphs 13, 20 or 35, or the    method of any one of paragraphs 36, 42, 48, 53, 58, 63, 68, 73, 78,    84, 89, 97, 102, 111, or the use of any one of paragraphs 119-131,    wherein the LAP-binding agent is a small molecule inhibitor, agent,    or compound.-   138. The composition of any one of paragraphs 13, 20 or 35, or the    method of any one of paragraphs 36, 42, 48, 53, 58, 63, 68, 73, 78,    84, 89, 97, 102, 111, or the use of any one of paragraphs 119-131,    wherein the LAP-binding agent is an RNA or DNA aptamer that binds or    physically interacts with LAP.-   139. The method of any one of paragraphs 36-101, 111-118 or the use    of any one of paragraphs 120-131, wherein the subject has or has    been diagnosed with cancer.-   140. The method or use of paragraph 139, wherein the subject has or    has been diagnosed with a brain tumor, a melanoma, or colorectal    cancer.-   141. The method or use of paragraph 140, wherein the brain tumor is    a glioblastoma.-   142. The method of any one of paragraphs 36, 42, 48, 53, 58, 63, 68,    73, 78, 84, 89, 97, 111 or the use of any one of paragraphs 119-131,    wherein the method further comprises administering an anti-cancer    therapy, chemotherapeutic or immunomodulatory agent to the subject.-   143. The method or use of paragraph 142, wherein the    immunomodulatory agent comprises an immune checkpoint inhibitor.-   144. The method or use of paragraph 143, wherein the immune    checkpoint inhibitor binds to one or more of the following: PD1,    PDL1, PDL2, CTLA4, LAG3, TIM3, TIGIT and/or CD103.-   145. The method or use of paragraph 143, wherein the immune    checkpoint inhibitor is a PD1, PDL1, and/or PDL2 inhibitory agent    selected from pembrolizumab; nivolumab; MK-3475; MPDL3280A;    MEDI0680; MEDI4736; AMP-224; and MSB0010718C.-   146. The method of or use of paragraph 142, wherein the method    further comprises administering a tumor or cancer antigen to the    subject.-   147. The method or use of paragraph 146, wherein the method    comprises administering the LAP binding agent concurrently or in    combination with dendritic cell (DC) vaccination.-   148. The method of paragraph 24, wherein the LAP-binding agent is an    isolated antibody or antigen-binding fragment thereof of any one of    paragraphs 1-11 or the pharmaceutical composition of paragraph 12.-   149. The composition of any one of paragraphs 13, 20 or 35, or the    method of any one of paragraphs 36, 42, 48, 53, 58, 63, 68, 73, 78,    84, 89, 97, 102, 111, or the use of any one of paragraphs 119-131,    wherein the LAP-binding agent is an isolated antibody or    antigen-binding fragment thereof of any one of paragraphs 1-11 or    the pharmaceutical composition of paragraph 12.

It is understood that the foregoing description and the followingexamples are illustrative only and are not to be taken as limitationsupon the scope of the invention. Various changes and modifications tothe disclosed embodiments, which will be apparent to those of skill inthe art, may be made without departing from the spirit and scope of thepresent invention. Further, all patents, patent applications, andpublications identified are expressly incorporated herein by referencefor the purpose of describing and disclosing, for example, themethodologies described in such publications that might be used inconnection with the present invention. These publications are providedsolely for their disclosure prior to the filing date of the presentapplication. Nothing in this regard should be construed as an admissionthat the inventors are not entitled to antedate such disclosure byvirtue of prior invention or for any other reason. All statements as tothe date or representation as to the contents of these documents arebased on the information available to the applicants and do notconstitute any admission as to the correctness of the dates or contentsof these documents.

All patents and other publications identified are expressly incorporatedherein by reference for the purpose of describing and disclosing, forexample, the methodologies described in such publications that could beused in connection with the present invention. These publications areprovided solely for their disclosure prior to the filing date of thepresent application. Nothing in this regard should be construed as anadmission that the inventors are not entitled to antedate suchdisclosure by virtue of prior invention or for any other reason. Allstatements as to the date or representation as to the contents of thesedocuments is based on the information available to the applicants anddoes not constitute any admission as to the correctness of the dates orcontents of these documents.

EXAMPLES Example 1

Membrane-bound LAP expression was up-regulated on FOXP3+CD4+ lymphocytesfrom tumors of head and neck cancer patients. LAP+CD4+ lymphocytes werefound as enhanced suppressor T cells in both blood and tumor ofcolorectal cancer (CRC) patients. The blood-derived LAP+CD4+ subsetsuppresses naive T cell proliferation in a TGF-β-dependent manner. Incolorectal cancer, 30% of intratumor CD4+FOXP3− regulatory T cells areLAP and LAG positive. They secrete IL-10 and produce membrane-boundTGF-β. Although IFN-γ is slightly higher on LAP positive vs. LAPnegative T cells in blood, tumor-infiltrating LAP positive T lymphocytes(LAP+ TILs) secrete significantly lower amounts of IFN-γ and higherIL-10 in comparison to LAP− TILs. Interestingly, these CD4+LAP+ TILswere found to be 50-fold more suppressive than CD4+LAP− cells and thiswas partially dependent on TGF-β.

Independently of TGF-β, LAP has biological functions that can promotecancer malignancy. Soluble LAP was shown to regulate trafficking ofhuman monocytes by serving as a chemo-attractant. Thus, high levels ofLAP in the brain tumor can attract monocytes from the periphery thatbecome tumor-associated macrophages in the tumor milieu, thuscontributing immunosuppression. In addition, immobilized LAP can induceexpression of MMP-9 and promote migration and invasion of tumor cellsthrough integrin signaling, while soluble LAP has the opposite effect.

Therapeutic Effects of Anti-LAP

Given the important regulatory role of CD4+LAP+ T cells we developedmonoclonal anti-LAP antibodies that recognize LAP expressed on the cellsurface. We generated both mouse- and human-specific monoclonal anti-LAPantibodies that deplete CD4+LAP+ T cells in vivo and block TGF-release.Our results described herein show efficacy of the mouse antibodies inthe decrease of melanoma, GBM and CRC tumor growth in syngeneic models(FIGS. 55A-55N). Specifically, B16 orthotopic tumor model was treatedwith anti-LAP (28G11 clone, FIGS. 55A, 55B). In addition, we testedanti-LAP in GBM/GL261 models: both orthotopic/intracranial andsubcutaneous models. Intracraneous model was treated with 16B4 (FIGS.55C-55F) and subcutaneous model was treated with either 16B4 (FIG. 55G)or 28G11 (FIG. 55H). Finally, colorectal carcinoma (CRC) models weretreated with 28G11 (FIGS. 55I-55N) or 16B4 (not shown). AOM/DSS-inducedorthotopic (FIGS. 55I-55K) and subcutaneous MC38 (FIG. 55L) and CT26(FIGS. 55M, 55N) CRC models were treated with anti-LAP. In all tumormodels, anti-LAP treatment resulted in therapeutic effects. Thus,anti-LAP antibodies can be used to block the immunosuppression mediatedby LAP in the models of melanoma, GBM and CRC.

We also acquired and tested syngeneic cancer models based on GL261original glioma cells, B16 melanoma cells and cells constitutivelyexpressing ovalbumin (GL261-OVA and B16-OVA) to study antigen-specificimmune responses in both intracranial and subcutaneous mouse models.

We identified a novel LAP+γδ T cell regulatory subset that manifests animmunosuppressive phenotype, suppresses the proliferation of naïve Tcells and induces FoxP3 expression further supporting theimmunosuppression. (Rezende et al., Nature Communications). In addition,we found that this cell population accumulates in the spleen of GBMbearing mice (FIG. 1E), indicating that these cells are involved inglioma-induced immunosuppression.

To study the role of LAP in the regulation of the immune response inGBM, we first analyzed LAP expression on different immune cellsinfiltrating GBM and in the periphery. We found that GBM-infiltratinglymphocytes and myeloid cells expressed high levels of LAP on theirsurface (FIGS. 1A-1D), indicating that it can play a role in immunesuppression in GBM.

To investigate which populations of LAP+ immune cells are important inGBM-mediated immunosuppression we compared the frequencies of differentLAP+ immune cells in GBM-bearing mice. Interestingly, we found thatγδ+LAP+ T cells strongly accumulated in the spleen of GBM-bearing mice(FIG. 1E). Since this subset has not been described in the literature,we investigated its phenotype and function. We found that the γδ+LAP+ Tlymphocytes possess a suppressive phenotype when compared to γδ+LAP− Tcells isolated from naïve mice (FIG. 2A, 2B). Cytokine expressionprofile by both qRT-PCR and flow cytometry shows that a pro-inflammatorymarker such as IFN-γ is down-regulated while immune suppressivecytokines (e.g., TGF-β and IL-10) are up-regulated. We then tested thefunction of the γδ+LAP+ T subset and found that these cells exhibitstrong suppressive abilities and are able to induce FoxP3 expression inan in vitro assay (FIG. 2C).

Since we found high expression of LAP on γδ T lymphocytes isolated fromtumor, we examined whether glioma cells can induce LAP expression onthese cells. As FIGS. 3A-3B show, co-culturing γδ+LAP− T lymphocyteswith glioma GL261 cells leads to increased LAP expression in vitro,indicating that glioma can cause immunosuppression by inducing LAPexpression on γδ T cells. To abolish the suppressive LAP effects onimmune system, we used anti-LAP antibodies to block LAP activity invivo.

To analyze the effects of anti-LAP antibodies on the immune system wetreated naïve mice with anti-LAP antibodies. We found that T cellproliferation and pro-inflammatory cytokine production were higher inanti-LAP treated animals as compared to mice treated withisotype-matched control (FIGS. 4A-4B) indicating that anti-LAP has theability to induce a pro-inflammatory immune response. (da Cunha,International Immunology, 2014)

To assess the therapeutic value of anti-LAP antibodies against tumor, weused a sub-cutaneous model of mouse glioma by implantation of GL261cells in the flanks of C57BL/6 mice. Following tumor implantation, micewere treated intraperitoneally (i.p.) with anti-LAP antibodies andrepeated treatments were given every other day. Isotype-matchednon-specific antibodies (IC) were employed as a negative control. Thetumors appeared around day 10 following implantation and grew initiallyin both treatment groups, and thereafter they markedly shrunk in theanti-LAP treated group after 14 days from the implantation when theimmunity is fully developed (FIGS. 55H, 5B). When we investigated theimmune response we found that anti-LAP blocked the tumor-inducedimmunosuppression that interferes with a proinflammatory immune response(FIGS. 5C-5K). Anti-LAP treatment led to higher expression of IFN-γ onCD4+ T cells and reduced FoxP3 on CD4+ T cells (FIGS. 5C and 5D,correspondingly). In addition, the treatment resulted in increasednumbers of CD8+ T cells (FIG. 5G) and their cytotoxic phenotype (FIGS.5H-5I).

Interestingly, the anti-LAP treatment resulted in a decreased frequencyof CD11b−Hi myeloid subset while CD11b−Int cells increased (FIGS. 57A,57B). Levels of tolerance-related markers PD-L1 and CD103 are reduced onCD11b−hi after anti-LAP treatment (FIG. 57C). LAP protein is mainlyexpressed on CD11b−hi cells, additionally indicating on a suppressivephenotype of this subset (FIG. 57D). We examined the immune profile ofthese two sub-populations. The subsets were sorted from naïve mice,stimulated with anti-CD40 antibody or lipopolysaccharide (LPS), followedby gene expression analysis. Upon activation, the CD11b−Hi populationexpressed higher levels of the immunosuppressive cytokines IL-10 andTGF-β and lower levels of the pro-inflammatory cytokine IL-12,indicating that this subset can have a regulatory role; anti-LAPtreatment eliminated these cells. (FIG. 57E). CD8 cells, co-culturedwith CD11b−hi, express lower levels of proinflammatory cytokinessupporting anti-tumor immune responses, IFN-γ and TNF-α, as compared toCD11b−int subset (FIG. 57F). Moreover, the CD11b−Hi subset expressed lowlevels of antigen presentation markers (FIGS. 57G, 57H) indicating thatthese cells have lower capacity to support antigen-specific immuneresponses. Finally, CD11b−hi cells do not support CD8+ T cells growthwhen culture in vitro (FIG. 57I). Thus, we found that anti-LAP treatmentreduces the number of myeloid cells with suppressive properties, whichfavors a stronger immune response and tumor elimination.

Since anti-LAP antibody treatment was very efficient in the eliminationof the peripheral tumor, we performed experiments to assess itspotential in an orthotopic mouse model of intracranial GBM. Followingthe implantation of GL261 glioma cells into the striatum usingstereotactic surgery, mice were treated with anti-LAP every other daystarting from day five following tumor implantation. As shown in FIGS.55C-55F, despite aggressive tumor progression, mice treated withanti-LAP survived longer, and this was associated with increasedinfiltration of CD8+ T cells into the brain tumor. Considering thestrong malignant nature of intracranial GBM, this result demonstrates atherapeutic potential of the anti-LAP antibodies against brain tumor andindicates the potential of a therapeutic effect of anti-LAP.

To investigate the role of LAP and TGF-β in human GBM, we analyzed TCGA(The Cancer Genome Atlas) data to determine if the expression ofmessenger RNA (common for both proteins) correlated with patientssurvival. We found an inverse correlation between high levels of themRNA expression (marked as TGF-β) and the survival of GBM patients (FIG.62) indicating that the gene encoding for LAP/TGF-β is involved in GBMpathogenesis. Similar results were observed for patients with othercancers, demonstrating a broad phenomenon of LAP expression machineryassociated with malignancy (FIGS. 62, 63).

Investigating the Immunosuppressive Role of LAP in Cancer.

We found that treatment with anti-LAP antibodies, either TW7-28G11 (FIG.58A) or TW7-16B4 (FIG. 39) result in a reduced accumulation of CD4+LAP+T cells in mice as indicated by detection of these cells using anon-competing anti-LAP clone (FIG. 58A). These results demonstrate thatanti-LAP treatment leads to depletion of CD4+LAP+ T cells in vivo.Recent studies indicate that LAP expressed by various immune cells canmediate immunosuppression. Using flow cytometry analysis we found thatLAP+CD4+ T cells isolated from B16 melanoma express higher levels ofimmunosuppression markers, FoxP3, LAG3, PD1, PD-L1, Tim3, CD103 (FIG.58B), suggesting suppressive abilities for these cells. To evaluate thesuppression properties of LAP+CD4+ T cells in cancer, we sorted LAP+CD4+T cells from the spleen of B16 tumor bearing mice (providing asufficient amount of LAP+ cells for the assay) and co-cultured them withnaïve CD4+ T cells in the presence of DCs. We observed almost two-foldreduced proliferation of the naïve T cells in the presence of LAP+CD4+ Tcells in comparison to the condition where no suppression cells wereadded (FIG. 58C). As a negative control, we used LAP-CD4+ T cells thatonly slightly decreased the T cell proliferation presumably due to thepresence of FoxP3+ T cells. Interestingly, CD4+LAP+ T cells isolatedfrom either spleen or draining lymph nodes (dLNs) of mice bearing B16melanoma had reduced suppression properties after anti-LAP treatment(FIG. 58D). Mice were treated with TW7-28G11 and CD4+LAP+ T cells weresorted by TW7-16B4 clone.

We also found that anti-LAP treatment leads to a reduced accumulation ofCD8+CD103+ T cells in tumor-bearing mice (subcutaneous GBM: FIGS. 23,28); intracranial GBM: FIGS. 47, 49; melanoma: FIG. 59A), suggestingthat these cells may possess suppressive abilities in tumor models.Indeed, while CD8+ T cells were necessary to mediate the therapeuticeffect of anti-LAP (FIG. 59B), CD103+CD8+ T cells isolated from spleenor dLNs of melanoma-bearing mice demonstrated suppressive abilities,which were decreased with anti-LAP treatment in an in vitro assay (FIG.59C). Moreover, adoptive transfer of these cells to CD8KO mice implantedwith melanoma caused worsening of tumor growth (FIG. 59D) indicatingthat CD103+CD8+ T cells suppress tumor-specific immunity in vivo.Phenotype analysis of these cells demonstrates that CD103+CD8+ T cellsexpress lower pro-inflammatory markers than CD103-cells (FIG. 59E).Thus, anti-LAP is able to target a novel regulatory CD8+ T cellpopulation in tumor.

To determine the levels of LAP expression on different immune cells inmice, intracranial GBM is induced in a syngeneic mouse model (GL261).The levels of LAP expression on the following immune subsets both in theperiphery and the brain are examined: αβ T lymphocytes (CD4+ and CD8+),γδ T lymphocytes, macrophages (CD11b+) and dendritic cells (DCs,CD11c+).

Mononuclear cells are isolated from GBM using percoll gradient andstained with anti-CD4, -CD8, -γδTCR, -CD11b, -CD11c antibodies eachcombined with anti-LAP antibodies for multiparametric flow cytometryanalysis. Levels of LAP expression on tumor-infiltrating and peripheralimmune cells isolated from the spleen of GBM-bearing and naïve mice arecompared.

We previously demonstrated LAP expression on human T lymphocytes anddendritic cells in normal conditions. To analyze the expression of LAPon GBM-associated human immune cells, isolated peripheral bloodmononuclear cells (PBMCs) from healthy donors and GBM subjects arestained for live T lymphocytes (CD4+), monocytes (CD11b+) and dendriticcells (mDCs, CD11c+Lin- and pDCs, CD11c−Lin-CD123+) with human-specificanti-LAP antibodies, according to our published methods.

Phenotype of LAP+ Immune Cells Infiltrating Intracranial GBM Isolated atDifferent Stages of the Disease Progression in Mouse and Human.

To examine the phenotype of LAP+ immune cells (αβ+ and γδ+ Tlymphocytes; CD11b+ and CD11c+ myeloid cells) gene profiling of LAP+vs.LAP− immune cells is performed by employing Nanostring-basedinflammatory arrays as we demonstrated earlier and then validating theexpression of specific genes by qRT-PCR (e.g., TGF-β, TNF-α, IL-10, andIL-12). The protein levels of inflammation-related and regulatory genes(e.g., IFN-γ, GRZB, CD107a, IL-10, FoxP3 on T cells and PD-L1, CD39,CD103 on myeloid cells) is determined under resting and stimulationconditions by flow cytometry and ELISA. To assess theantigen-presentation potential of the myeloid cells, the levels of MHCI,MHCII, CD80, CD86 and CD40 are measured. These studies are performed atdifferent disease stages to determine how LAP expression and cellphenotype are linked to disease progression.

Complementary to our mice studies, the phenotype of LAP+ immune cellsisolated from blood (PBMCs) and tumor of glioma patients compared toblood of healthy donors is examined. The expression of inflammationgenes by Nanostring and qRT-PCR (e.g., TGF-β, TNF-α, and IL-10) isdetermined. The protein levels of immune-related genes (e.g., IFN-γ,GRZB, IL-10, FoxP3 on T cells and PD-L1, CD39, CD103 on myeloid cells)under resting and stimulation conditions by flow cytometry is examined.

Functional analysis of LAP+ Regulatory Immune Cells Isolated from Tumor

To study the function of immune cells expressing membrane-bound LAP,their ability to influence T cell function is determined. T lymphocytesand myeloid cells are examined. The following parameters are tested toanalyze the suppressive abilities of corresponding LAP+ and LAP− cells:a) Function of lymphocytes: T cell proliferation in the presence ofLAP+vs. LAP− T cells (both αβ+ and γδ+ T lymphocytes) is examined exvivo. Two types of assays using non-specific responder T cell activation(with anti-CD3) and antigen-specific activation (with ovalbumin) usingOT-II mice (OVA-TCR Tg) are performed.

To study the functional role of αβ+LAP+ and γδ+LAP+ T cells in vivo,adoptive transfer these cells into GBM-bearing mice is performed, andGBM progression followed by monitoring tumor growth (by MRI), assessingsurvival and examining local and systemic adaptive and innate immuneresponses.

Phagocytosis of CD11b+LAP+ cells is examined using a macrophageCytoSelect phagocytosis assay (with zymozan substrate). Effects on Tcells are measured by co-culturing macrophages (CD11b+LAP+) anddendritic cells (CD11c+LAP+) with naïve T cells and by monitoring theirgrowth by T cell proliferation assay. These experiments interrogate theantigenpresenting ability and suppressive effects of myeloid cells inGBM.

The function of human lymphocytes and myeloid cells isolated from PBMCsof GBM patients and healthy donors (by FACS sorting) is examined andtheir immune suppression potential evaluated using a T cellproliferation/suppression assay.

Given the immunosuppressive properties of LAP, immune cells expressingthis protein express other suppressive markers (FIG. 58B) anddemonstrate regulatory roles in the functional assays (FIGS. 58C, 58D).Most biologic roles of LAP described so far were attributed to the αβ+ Tcell functions. As demonstrated herein, we found that γδ+LAP+ T cellsalso possess suppressive abilities (FIGS. 2A-2D) and are stronglyupregulated systemically in GBM-bearing mice (FIG. 1E). Our experimentsevaluate their pathological function in the context of GBM. In addition,our studies explore a previously uninvestigated role of LAP+ myeloidcells in immune suppression.

Evaluating the Therapeutic Potential of Anti-LAP Antibodies in theTreatment of a GBM Intracranial Mouse Model.

Our results demonstrate that anti-LAP antibodies eliminate tumor growthin a peripheral glioma model and show that they can increase survival inan intracranial GBM model (FIGS. 55C-55H). The effects of the anti-LAPantibodies developed in our lab on the immune system and whether thismodulation has a therapeutic effect in an intracranial GBM model aresystematically evaluated. Effects of the anti-LAP antibody treatment onthe immune response in mice bearing tumor.

To study how anti-LAP influences the immune system, naïve and GBM micebearing intracranial tumors are treated with anti-LAP and IC antibodiesi.p. every other day for three weeks. Spleens and tumors are harvestedand the adaptive and innate immune responses examined. The effects ofanti-LAP antibody on both the adaptive and innate immune response aredetermined.

1) Adaptive immune response. Th1/Th2 and cytotoxic T lymphocyte (CTL)responses are evaluated by analyzing the frequencies of T lymphocytesubsets (CD4+ and CD8+) in tumor and spleen. The expression of surfacemembrane-bound and intracellular immunomodulators, such as IFN-γ, onboth subsets are examined; LAP, LAG, CD103, PD1, Tim3, IL-10, FoxP3,IL-17 and TGF-β on CD4+ T cells; CD107, GRZB and perforin on CD8+ Tlymphocytes by flow cytometry. In GL261 glioma (FIGS. 27 and 41, treatedby 16B4) and B16 melanoma (FIG. 56A, treated by 28G11) models, we foundthat tumors of mice treated with anti-LAP are infiltrated by increasednumbers of CD8+ T cells. In the melanoma model, following anti-LAPtreatment, CD8+ tumor-infiltrating T cells had better proliferationcapacity, based on the expression of Ki67 and expressed higher levels ofpro-inflammatory mediators (FIG. 56A). Moreover, the ratio of CD8+ Tcells/Tregs was also higher after anti-LAP treatment. The number of CD8+T cells and their pro-inflammatory phenotype was also higher in theperiphery (FIG. 56B).

2) Innate immune response. Tumor-infiltrating antigen-presenting cellsincluding dendritic cells (CD11c+) and macrophages (CD11b+) areinvestigated by examining their frequencies and expression ofsuppression markers (PD-L1, CD39, CD103), antigen-presentation markers(MHCI, MHCII) and co-stimulatory molecules (CD40, CD80, CD86) by flowcytometry. FIGS. 57A-57J.

The ability of these myeloid cell subsets to produce different cytokines(IL-1β, IL-6, IL10, IL-12, IL-23, and TGF-β) were assessed. Macrophagesand DCs were sorted, stimulated with anti-CD40 antibody orlipopolysaccharide (LPS), followed by gene expression analysis.

To analyze functional immune response following anti-LAP in GBM, GL261glioma cells expressing ovalbumin (GL261-OVA) are injectedintracranially and mice treated with anti-LAP antibodies. OVA-specificCD4+ and CD8+ T cell immune response are measured in these mice.

Therapeutic Value of Anti-LAP Antibodies in the Experimental GBM Model.

Antibodies targeting GBM associated immunosuppression can be used as atreatment. The anti-LAP antibodies generated in our lab are used to testtheir therapeutic potential in GBM.

GL261 cells were implanted intracranially in C57BL/6 mice which werethen treated with anti-LAP (100 μg/mouse) every other day starting fromthe second day following tumor implantation. GBM growth was monitored bymagnetic resonance imaging (MRI) and survival (FIGS. 85A-85N). GBMinvasion and angiogenesis is analyzed by hematoxylin and eosin (H&E) andimmunohistochemical anti-CD31 staining, 3) transcriptional andfunctional profile of macrophages recruited to GBM is performed byNanostring and their effects on T-cell proliferation in vitro; and 4)local and peripheral immune responses are evaluated by analyzing thefrequency of cytotoxic and regulatory T cells and their function. SinceLAP can induce cell invasion, whether GBM invasion is reduced byanti-LAP treatment is analyzed in vitro (Boyden chambers) and in vivo(histopathology).

As described herein, using an aggressive intracranial GBM model, weobserved enhanced survival of mice after treatment with anti-LAP. Insome embodiments of the aspects described herein, higher doses ofanti-LAP antibody and starting treatment early can be used to enhancethe therapeutic effects of anti-LAP antibodies against GBM. In addition,given that LAP is produced by different immune cells in the intracranialGBM and can attract monocytes, the anti-LAP treatment can result inlower tumor infiltration by macrophages. Considering the pathologicalcontribution of myeloid cells to GBM, anti-LAP treatment can lead toreduced invasion and local tumor immunosuppression, featuressignificantly contributed by macrophages.

Enhanced Immune T Cells Memory Against Tumor-Associated Antigens.

We found that tumor-infiltrating T cells in mice bearing intracranialGBM and treated with anti-LAP expressed higher levels of memory markers(IL7R and CD44, FIG. 67). Based on these results, we hypothesized thatanti-LAP can enhance immune memory and benefit from prevaccination witha DC vaccine expressing a tumor-associated antigen. We tested thishypothesis by pre-vaccinating mice with ovalbumin loaded dendriticcells, treating the mice with anti-LAP (16B4 clone) and injectingintracranial tumors (GL261-OVA) a week later (FIG. 60A). We followeddisease development by MRI imaging and survival. All mice treated withanti-LAP did not develop tumors, while four out of five IC treated micedeveloped GBM and had to be sacrificed thus supporting our hypothesis(FIGS. 60B, 60C). To test the long-term immunity, remaining mice wererechallenged three months later with subcutaneous GL261-OVA. These micedid not develop tumors indicating that they preserved immune memoryagainst this tumor. Anti-LAP treated mice expressed higher levels ofIL7R (FIGS. 60D, 60E) and tetramer signal was higher on CD8+ T cells(FIG. 60F) as compared to naïve mice or the mouse treated with ICsuggesting that anti-LAP increases CD8+ tumor-antigen-specific T cells.These observations were supported by similar observations in a melanomamodel treated with 28G11 clone of anti-LAP (FIG. 61). Thus, anti-LAP mayenhance immune memory and would potentially benefit from concomitantvaccination with tumor-associated antigens.

Example 2

Preparation of Anti-LAP Antibody Constructs

Total RNA was isolated from TW7-28G11 hybridoma cells using TRIZOL®Reagent (Thermo Fisher Scientific), according to the technical manualfor TRIZOL® Reagent. The total RNA was analyzed by agarose gelelectrophoresis.

Total RNA was reverse transcribed into cDNA using isotype-specificanti-sense primers or universal primers following the technical manualof PRIMESCRIPT™ 1st Strand cDNA Synthesis Kit. The antibody fragments ofV_(H) and V_(L) from TW7-28G11 hybridoma cells were amplified accordingto the standard operating procedure of RACE of GenScript.

Amplified antibody fragments were separately cloned into a standardcloning vector using standard molecular cloning procedures.

Colony PCR screening was performed to identify clones with inserts ofcorrect sizes. No less than five single colonies with inserts of correctsizes were sequenced for each antibody fragment.

Five single colonies from TW7-28G11 hybridoma cells with correct V_(H)and V_(L) insert sizes were sent for sequencing. The V_(H) and V_(L)genes of five different clones were found nearly identical. Theconsensus nucleotide sequence, listed herein as SEQ ID NO: 7 and SEQ IDNO: 12, are believed to be the sequence of the antibody produced by thehybridoma TW7-28G11.

The V_(H) CDR1-CDR3 amino acid sequences of the TW7-28G11 antibody areprovided herein as SEQ ID NOs: 9-11. The V_(L) CDR1-CDR3 amino acidsequences of the TW7-28G11 antibody are provided herein as SEQ ID NOs:14-16. Suitable framework sequences using the V_(H) and/or V_(L) CDRsequences of the TW7-28G11 antibody to generate humanized, CDR-grafted,and/or chimeric antibodies and/or antigen-binding fragments thereof canbe identified and selected using techniques known to those of skill inthe art and as described elsewhere herein.

Total RNA is isolated from TW7-16B4 hybridoma cells using, for example,TRIZOL® Reagent. The total RNA is analyzed using, for example, agarosegel electrophoresis.

Total RNA is reverse transcribed into cDNA using, for example,isotype-specific anti-sense primers or universal primers following thetechnical manual of PRIMESCRIPT™ 1 st Strand cDNA Synthesis Kit. Theantibody fragments of V_(H) and V_(L) from TW7-16B4 hybridoma cells areamplified using, for example, the standard operating procedure of RACEof GenScript.

Amplified antibody fragments are separately cloned into a standardcloning vector using standard molecular cloning procedures.

Colony PCR screening is performed to identify clones with inserts ofcorrect sizes. For example, at least three or at least five singlecolonies with inserts of correct sizes are sequenced for each antibodyfragment.

Single colonies from TW7-16B4 hybridoma cells with correct V_(H) andV_(L) insert sizes are sent for sequencing and a consensus nucleotidesequence identified from which the amino acid sequences of the V_(H) andV_(L) and corresponding CDR1-CDR3 regions are identified.

Suitable framework sequences using the V_(H) and/or V_(L) CDR sequencesof the TW7-16B4 antibody to generate humanized, CDR-grafted, and/orchimeric antibodies and/or antigen-binding fragments thereof can beidentified and selected using techniques known to those of skill in theart and as described elsewhere herein.

The invention claimed is:
 1. An anti-LAP antibody, or antigen-bindingfragment thereof, wherein said anti-LAP antibody comprises: (i) a heavychain CDR1 having the amino acid sequence of SEQ ID NO: 9; (ii) a heavychain CDR2 having the amino acid sequence of SEQ ID NO: 10; (iii) aheavy chain CDR3 having the amino acid sequence of SEQ ID NO: 11; (iv) alight chain CDR1 having the amino acid seequence of SEQ ID NO: 14; (v) alight chain CDR2 having the amino acid seequence of SEQ ID NO: 15; and(vi) a light chain CDR3 having the amino acid sequence of SEQ ID NO: 16;and wherein the anti-LAP antibody, or antigen-binding fragment thereof,comprises a heavy chain variable region sequence of SEQ ID NO: 8,wherein the heavy chain variable region comprises four framework regionswhich are each at least 75% identical to the corresponding frameworkregion of the heavy chain variable region of SEQ ID NO: 8; and a lightchain variable region sequence of SEQ ID NO: 13, wherein the light chainvariable region comprises four framework regions which are each at least75% identical to the corresponding framework region of the light chainvariable region of SEQ ID NO: 13; and wherein at least one of theframework regions of either the heavy chain variable region, the lightchain variable region, or both, are not 100% identical to the frameworkregion of either SEQ ID NO: 8 or SEQ ID NO: 13, respectively.
 2. Theanti-LAP antibody, or antigen-binding fragment thereof, of claim 1,wherein the anti-LAP antibody further comprises a human constant regionselected from the group consisting of IgG, IgE, IgM, IgD, IgA, and IgY.3. The anti-LAP antibody, or antigen-binding fragment thereof, of claim1, wherein the anti-LAP antibody further comprises a human IgG constantregion.
 4. The anti-LAP antibody, or antigen-binding fragment thereof,of claim 1, wherein the antigen-binding fragment is a Fab fragment, aFab′ fragment, a Fd fragment, a Fd′ fragment, a Fv fragment, a dAbfragment, a F(ab′)₂ fragment, a single chain fragment, a diabody, or alinear antibody.
 5. A method of promoting the formation of memory Tcells specific for an antigen of interest in a subject in need thereof,the method comprising administering (i) the anti-LAP antibody, orantigen binding fragment thereof, of claim 1, and (ii) the antigen ofinterest to the subject.
 6. The method of claim 5 wherein CD44+ and/orIL7R+ T cells are increased following administration of the anti-LAPantibody, or antigen binding fragment thereof.
 7. The method of claim 5wherein the antigen of interest comprises a tumor antigen or an antigenexpressed by an infectious pathogen.
 8. The method of claim 7 whereinthe tumor antigen is administered as a dendritic cell vaccine.
 9. Themethod of claim 1 wherein the anti-LAP antibody, or antigen bindingfragment thereof, is a monoclonal antibody or antigen-binding fragmentthereof.
 10. The method of claim 1 the anti-LAP antibody, or antigenbinding fragment thereof, is chimeric, humanized, or fully human.
 11. Amethod of increasing tumor-specific immunity comprising administering toa subject in need thereof an effective amount of the anti-LAP antibody,or antigen-binding fragment thereof, of claim 1 to increasetumor-specific immunity in the subject.
 12. A method of increasing thenumber of CD8+ cytotoxic T cells in a tumor, the method comprisingadministering to a subject with a tumor an effective amount of theanti-LAP antibody, or antigen-binding fragment thereof, of claim 1 toincrease the number of CD8+ cytotoxic T cells in the tumor.
 13. A methodof increasing the number of peripheral CD4+ T cells expressing IFN-γ ina subject in need thereof, the method comprising administering to thesubject an effective amount of the anti-LAP antibody, or antigen-bindingfragment thereof, of claim 1 to increase the number of peripheral CD4+ Tcells expressing IFN-γ in the subject.
 14. A method of increasing thenumber of peripheral CD8+ T cells expressing granzyme B in a subject inneed thereof, the method comprising administering to the subject aneffective amount of the anti-LAP antibody, or antigen-binding fragmentthereof, of claim 1 to increase the number of peripheral CD8+ T cellsexpressing granzyme B in the subject.
 15. A method of decreasing thenumber of FoxP3+ regulatory T cells in a tumor, the method comprisingadministering to a subject with a tumor an effective amount of theanti-LAP antibody, or antigen-binding fragment thereof, of claim 1 todecrease the number of FoxP3+ regulatory T cells in the tumor.
 16. Amethod of inhibiting expression of an immunosuppressive factor or markerby CD8+ and/or CD4+ T cells in a tumor, the method comprisingadministering to a subject with a tumor an effective amount of theanti-LAP antibody, or antigen-binding fragment thereof, of claim 1 toinhibit the expression of an immunosuppressive factor or marker by CD8+and/or CD4+ T cells in the tumor.
 17. A pharmaceutical compositioncomprising the anti-LAP antibody, or antigen-binding fragment thereof,of claim 1, and a pharmaceutically acceptable excipient.
 18. Thepharmaceutical composition of claim 17, further comprising an inhibitorof TGF-β signaling.
 19. The pharmaceutical composition of claim 17,further comprising an immunomodulatory or chemotherapeutic agent.
 20. Amethod of treating a cancer in a human subject in need thereofcomprising administering the pharmaceutical composition of claim 17.